SLC500 - Allen-Bradley Co.

User

Manual

SLC 500™

Thermocouple/mV

Analog Input Module

(Catalog Number 1746-NT8)

Allen-Bradley

Important User Infor m ation Because o f t he var iety o f uses fo r the product s descri bed in th is publ icat ion,

those re spo nsible for t he ap plica tion a nd use of this c ont rol equ ipment mus t

satisfy themselves that all necessary steps have been taken to assure that

each application and use meets all performance and safety requirements,

including any applicable laws, regulations, codes and standards.

The illustrations, charts, sample programs and layout examples shown in

this gui de are inte nded solely for purp oses of exampl e. Since there ar e many

variables and requirements associated with any particular installation,

Allen-Bradley does not assume responsibility or liability (to include

intell ectual p roperty li ability) f or actual us e based upon t he examples shown

in this publication.

Allen-Bradley publication SGI-1.1, Safety Guidelines for the Application,

Installation and Maintenance of Solid-State Control (available from your

local Allen-Bradley office), describes some important differences between

solid-state equipment and electromechanical devices that should be taken

into consideration when applying products such as those described in this

publication.

Reproduction of the contents of this copyrighted publication, in whole or

part, without written permission of Rockwell Automation, is prohibited.

Throughout this manual we use notes to make you aware of safety

considerations:

Attention statements help you to:

•identify a hazard

•avoid a hazard

•recognize the consequences

Important:Identifies infor m ation that is critica l for successf ul applicatio n

and understanding of the product.

PLC, PLC-2, PLC-3, and PLC-5 are registered trademarks of Rockwell Automation. SLC, SLC 500, SLC 5/01, SLC 5/02, SLC 5/03, SLC

5/04, and SLC 5/05 are registered trademarks of Rockwell Automation. Belden is a trademark of Belden, Inc.

ATTENTION: Identifies information about practices or

circumstances that can lead to personal injury or death,

property damage or economic loss

Publication 1746-6.22

Table of Contents

Preface Who Should Use This Manual . . . . . . . . . . . . . . . . . . . . . . . . .P-1

What This Manual Covers . . . . . . . . . . . . . . . . . . . . . . . . . . . .P-1

Related Allen-Bradley Documents . . . . . . . . . . . . . . . . . . . . . .P-2

Common Techniques Used in this Manual . . . . . . . . . . . . . . . .P-3

Allen-Bradley Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P-3

Local Product Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P-3

Technical Product Assistance . . . . . . . . . . . . . . . . . . . . . . .P-3

Your Questions or Comments on this Manual. . . . . . . . . . .P-3

Module Overview Chapter 1

General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Input Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Hardware Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Diagnostic LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

Module Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Module Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Linear Millivolt De vice Co mpatibility. . . . . . . . . . . . . . . . . . . 1-6

Installing And Wiring

Your Module Chapter 2

Electrostatic Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Considerations for a Modular System. . . . . . . . . . . . . . . 2-2

Fixed I/O Chassis - I/O Module Compatibility. . . . . . . . . 2-3

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Module Installation and Removal . . . . . . . . . . . . . . . . . . . . . . . 2-5

Terminal Block Removal. . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Wiring Your Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Preparing and Wiring the Cables . . . . . . . . . . . . . . . . . . 2-8

Cold-Junction Compensation (CJC). . . . . . . . . . . . . . . . . . 2-10

ii Table of Contents

Publication 1746-6.22

Thin gs To Consider

Before Using

Your Module Chapter 3

Module ID Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-1

Module Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-2

Output Image - Configuration Words. . . . . . . . . . . . . . .3-2

Input Image - Data Words and Status

Words. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3

Channel Filter Frequency Selection . . . . . . . . . . . . . . . . . .3 -3

Channel Cut-Off Frequency. . . . . . . . . . . . . . . . . . . . . .3-4

Channel Step Response . . . . . . . . . . . . . . . . . . . . . . . .3-6

Update Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-7

Update Time Calculation Example. . . . . . . . . . . . . . . . .3-7

Channel Turn-On, Turn-Off, and Reconfiguration

Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

Auto-Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-8

Response to Slot Disabling . . . . . . . . . . . . . . . . . . . . . . . .3-9

Input Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-9

Output Response. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-9

Channel Configu rati on,

Data, and Status Chapter 4

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-1

Channel Configuration Procedure . . . . . . . . . . . . . . . . . . .4-2

Select Channel Enable (Bit 0) . . . . . . . . . . . . . . . . . . . .4-5

Select Input Types (Bits 1 through 4). . . . . . . . . . . . . . .4-5

Select Data Format (Bits 5 and 6) . . . . . . . . . . . . . . . . .4-5

Using Scaled-for-PID and

Proportional Counts. . . . . . . . . . . . . . . . . . . . . . . . . .4 -6

Effective Resolutions . . . . . . . . . . . . . . . . . . . . . . . .4-6

Scaling Examples. . . . . . . . . . . . . . . . . . . . . . . . . . .4-7

Select Open-Circuit State (Bits 7 and 8) . . . . . . . . . . . .4-9

Select Temperature Units (Bit 9) . . . . . . . . . . . . . . . . .4-10

Select Ch an nel Filt e r Fre qu ency

(Bits 10 and 11) . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-10

Unused Bits (Bits 12 through 14) . . . . . . . . . . . . . .4-11

Select Input Image Type (Bit 15) . . . . . . . . . . . . . .4-11

Channel Data/Status Word . . . . . . . . . . . . . . . . . . . . . . . .4-12

Channel Status Checking . . . . . . . . . . . . . . . . . . . . . . . . .4-12

Channel Status (Bit 0). . . . . . . . . . . . . . . . . . . . . . .4-14

Input Type Status (Bits 1 through 4). . . . . . . . . . . .4-14

Data Format Type Status (Bits 5 and 6). . . . . . . . .4-14

Open-Circuit Type Status (Bits 7 and 8). . . . . . . . .4-14

Temperature Units Type Status (Bit 9) . . . . . . . . . .4-14

Table of Contents iii

Publication 1746-6.22

Channel Filter Frequency

(Bits 10 and 11) . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

Open-Circuit Error (Bit 12) . . . . . . . . . . . . . . . . . . . 4-14

Under-Range Error (Bit 13) . . . . . . . . . . . . . . . . . . 4-15

Over-Range Error (Bit 14) . . . . . . . . . . . . . . . . . . . 4-15

Channel Error (Bit 15) . . . . . . . . . . . . . . . . . . . . . . 4-15

Programming Examples Chapter 5

Basic Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Automatic Monitoring T hermocouples

and CJC Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Verifying Channel Configuration Changes . . . . . . . . . . . . . 5-3

Interfacing to the PID Instruction . . . . . . . . . . . . . . . . . . . . 5-7

Monitoring Channel Status Bits . . . . . . . . . . . . . . . . . . . . . 5-8

PLC 5 Example with NT8 in Remote I/O Rack . . . . . . . . 5-14

Troubleshooting

Your Module Chapter 6

Module and Channel Diagnostics . . . . . . . . . . . . . . . . . . . 6-1

Module Diagnostics at Powerup . . . . . . . . . . . . . . . . . . 6-1

Channel Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

LED Troubleshooting Tables. . . . . . . . . . . . . . . . . . . . . 6-2

Channel-status LEDs (Green). . . . . . . . . . . . . . . . . . . . 6-3

Open-circuit Detection (Bit 12) . . . . . . . . . . . . . . . . . . . 6-3

Out-of-Range Detection (Bit 13 for Under Range,

bit 14 for Over Range) . . . . . . . . . . . . . . . . . . . . . . . 6-3

Channel Error (Bit 15) . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4

Module Status LED (Green) . . . . . . . . . . . . . . . . . . . . . 6-4

Interpreting I/O Error Codes . . . . . . . . . . . . . . . . . . . . . . . 6-4

Maintain ing Your

Module And Safety

Consideration s Chapter 7

Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

iv Table of Contents

Publication 1746-6.22

Modu le S pecificatio ns Appendix A

Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1

Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . .A-2

Input Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A -2

Overall Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2

Millivolt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-3

Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-5

Using Grounded Junc ti on,

Ungrounded Junction,

and Exposed Junction

Thermoc ouples Append ix B

Thermocouple Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1

Grounded Junction. . . . . . . . . . . . . . . . . . . . . . . . . .B-2

Ungrounded (Insulated) Junction . . . . . . . . . . . . . . .B-2

Exposed Junction. . . . . . . . . . . . . . . . . . . . . . . . . . .B-2

Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-2

Grounded Junction Thermocouples. . . . . . . . . . . . . . . .B-3

Exposed Junction Thermocouples. . . . . . . . . . . . . . . . .B-4

Glossary

Index

Publication 1746-6.22

Preface

Read this preface to familiarize yourself with this user manual. This

preface covers:

• who should use this manual

• what this manual provides

• related Allen-Bradley documents

• common techniques used in this manual

• Allen-Bradley support

Who Should Use This

Manual Use this manual if you design, install, program, or maintain a control

system that uses Allen-Bradley Small Logic Controllers (SLC).

You should have a basic understanding of SLC 500 products. You

should also understand electronic process control and the ladder

program instructions required to generate the electronic signals that

control your application. If you do not, contact your local Allen-

Bradley representative for the proper training before using these

products.

What This Manual

Covers This manual covers the 1746-NT8 thermocouple/millivolt analog

input module. It contains the information you need to install, wire,

use, and maintain these modules. It also provides diagnostic and

troubleshooting help should the need arise.

P-2 Preface

Publication 1746-6.22

Related Allen-Bradley

Documents The following table lists several Allen-Bradley documents that may

help you as you use these products.

To obtain a copy of any of the Allen-Bradley documents listed,

contact your local Allen-Bradley office or distributor.

Publication Num b er Title

1747-2.30 SLC 500 System Overview

SGI-1.1 Application Considerations for Solid State Controls

1770-4.1 Allen-Bradley Programmable Controller Grounding and

Wiring Guidelines

1747-6.2 Installation & Operation Manual for Modular Hardware Style

Programmable Controllers

1747-6.21 Installation & Operation Manual for Fixed Hardware Style

Programmable Controllers

1747-6.15 SLC 500 Instruction Set Reference Manual

ABT-1747-TSG001 SLC 500 Software Programmers’s Quick Reference Guide

1747-NP002 Allen-Bradley HHT (Hand-Held Terminal) User Manual

1747-NM009 Getting Started Guide for HHT (Hand-Held Terminal)

SD499 Allen-Bradley Publication Index

AG-7.1 Allen-Bradley Industrial Automation Glossary

Preface P-3

Publication 1746-6.22

Common Techniques

Used in this Manual The following conventions are used throughout this manual:

• Bulleted lists such as this one provide information, not

procedural steps.

• Numbered lists provide sequential steps or hierarchical

information.

• Text in this font indicates words or phrases you should typ e.

• Key names appear in bold, capital letters within brackets (for

example, [ENTER]).

Allen-Bradley Support Allen-Bradley offers support services worldwide, with over 75 Sales/

Support Offices, 512 authorized Distributors and 260 authorized

Systems Integrators located throughout the United States alone, plus

Allen -Brad ley representative s in every majo r count ry in the world.

Local Product Support

Contact your local Allen-Bradley representative for:

• sales and order support

• produ ct tec hni cal traini ng

• warranty support

• support service agr eements

Technical Product Assistance

If you need to contact Allen-Bradley for technical assistance, please

review t h e in formation in the Troubleshooting cha pt er first. Then call

your local Allen-Bradley representative.

Your Questions or Comments on this Manual

If you find a problem with this manual, please notify us of it on the

enclosed Publication Problem Report.

If you have an y suggest ions f or how this manual coul d be made mo re

useful to you, please contact us at the address below:

Allen-Bradley

Control and Information Group

Technical Communication, Dept. A602V, T122

P.O. Box 2086

Milwaukee, WI 53201–2086

Publication 1746-6.22

Chapter

Module Overview

This chapter describes the thermocouple/mv input module and

explains how the SLC 500 processor reads thermocouple or millivolt

analog input data from the module.

Read this chapter to familiarize yourself further with your

thermocouple/mV analog input module. This chapter covers:

• general description and hardware features

• an overview of system and module operation

• block diagram of channel input circuits

General Description This module i s design ed exclus ively to mount into 1746 I /O racks for

use with SLC 500 fixed and modular systems. The module stores

digitally converted thermocouple/mV analog data in its image table

for retrieval by all fixed and modular SLC 500 processors. The

module supports connections from any combination of up to eight

thermocouple/mV analog sensors.

Input Ranges

The following tables define thermocouple types and associated

temperature ranges and the millivolt analog input signal ranges that

each of the module’s input channels support. To determine the

practical temperature range of your thermocouple, refer to the

specifications in appendix A.

Thermocouple Temperature Ranges

Millivolt Input Ranges

Type °C Temperature Range °F Temperature Range

J-210°C to +760°C -346°F to +1400°F

K -270°C to +1370°C -454°F to +2498°F

T -270°C to +400°C -454°F to +752°F

B +300°C to +1820°C +572°C to +3308°F

E -270°C to +1000°C -454°F to +1832°F

R 0°C to +1768°C +32 F to +3214°F

S 0°C to +1768°C +32°F to +3214°F

N 0°C to +1300°C +32°F to +2372°F

CJC Sensor -25°C to +105°C -13°F to +221 °F

-50 to +50 mV

-100 to +100 mV

1-2 Module Overview

Publication 1746-6.22

Each input channel is individually configured for a specific input

device, and provides open-circuit, over-range, and under-range

detection and indication.

Hardware Features

The module fi ts into any single slot for I/O mo dules in eith er an SLC

500 modular system or an SLC 500 fixed system expansion chassis

(1746-A2) , except t he zer o slot whi ch i s res er ved for the p roc ess or. It

is a Class 1 module using 8 input words and 8 output words.1

The module contains a removable terminal block providing

connections for eight thermocouple and/or analog input devices. On

the term inal blo ck are two cold-ju nctio n compens ati on (CJC) sens ors

that compensate for the cold junction at ambient temperature. It

should also be noted there are no output channels on the module.

Configure the module with software rather than with jumpers or

switches.

1. Requires use of a Block Transfer when used in a remote rack with a 1747-ASB.

Important: Ther e is a jumper (JP1) on th e circuit board. The modul e

is shipped with the jumper in the up position as

illus trated belo w . Do not c hange the positio n of JP1. The

jumper is used for test purposes only.

SLC 500

CAT

SERIAL NO.

THERMOCOUPLE/mV INPUT MODULE

MADE IN USAFAC 1M

INPUT SIGNAL RANGES

THERMOCOUPLE TYPES:

VOLTAGE:

±100mVDC to +100mVDC

±50mVDC to +50mVDC

SER

FRN)ULLISTED IND. CONT. EQ.

FOR HAZ. LOC. A196

CLASS I, GROUPS A, B, C AND D, DIV.2

OPERATING

)

SA J, K, T, E, R, S, B, N

TEMPERATURE

CODE T3C

1746 NT4

NT4±xxx x

MODULE

CHANNEL

STATUS

THERMOCOUPLE/mV

INPUT

CJC A+

CJC A-

CHL 0+

CHL 0-

SHIELD

CHL 1+

CHL 1-

CHL 2+

CHL 2-

SHIELD

CHL 3+

CHL 3-

CHL 4+

CHL 4-

SHIELD

CHL 5+

CHL 5-

CHL 6+

CHL 6-

SHIELD

CHL 7+

CHL 7-

CJC B+

CJC B-

1746-NT8

JP1

Side Label

Self-Locking Tabs

Door Label

Channel Status

LEDs (Green)

Module Status

LED (Green)

Removable

Terminal Blo ck

CJC Sensors

Cable Tie Slots

Jumper - Do Not Move.

Module Overview 1-3

Publication 1746-6.22

Hardware Features

Diagno stic LEDs

The module contains diagnostic LEDs that help you identify the

source of proble ms tha t may occur dur ing power -up o r durin g normal

operati on. Power -up and channel diagnostic s are explained in Chapter

6, Testing Your Module.

System Overview The module communicates with the SLC 500 processor and receives

+5V dc and +24V dc power from the system power supply through

the parallel backplane interface. No external power supply is

required. You may install as many thermocouple modules in the

system as the power supply can support.

Each module channel can receive input signals from a thermocouple

or a mV analog input device. You configure each channel to accept

either one. When configured for thermocouple input types, the

module converts analog input voltages into cold-junction

compensated and linearized, digital temperature readings. The

module uses National Institute of Standards and Technology (NIST)

ITS-90 for thermocouple linearization.

When configured for millivolt analog inputs, the module converts

analog values directly into digital counts. The module assumes that

the mV input signal is linear.

System Operation

At power-up, the module checks its internal circuits, memory, and

basic functions. During this time the module status LED remains off.

If the module finds no faults, it turns on its module status LED.

Hardware Function

Channel Status LED Indicators Display operating and fault status of channels 0-7

Module Status LED Displays operating and fault status of the module

Side Label (Nameplate) Provides module information

Removable Terminal Block Provides electrical connection to input devices

Door Label Permits easy terminal identification

Cable Tie Slots Secure and route wiring from module

Self Locking Tabs Secure module in chassis slot

SLC 500

Processor

Thermocouple

Input

Module

Thermocouple or mV

Analog Signals

Channel Data Word

Channel Status Word

Channel Configuration Word

1-4 Module Overview

Publication 1746-6.22

After completing power-up checks, the module waits for valid

channel configuration data from your SLC ladder logic program

(channel status LEDs are off). After channel configuration data is

transferred and channel enab le bits are set , th e enabled channe l status

LEDs turn on. Then the channel continuously converts the

thermocouple or millivolt input to a value within the range you

selected for the channel.

Each time the module reads an input channel, the module tests that

data for a fault, i.e. over-range or under-range condition. If open-

circuit detection is enabled, the module tests for an open-circuit

condition. If it detects an open-circuit, over-range, or under-range

conditi on, th e module sets a uniq ue bit i n the ch anne l sta tus word a nd

causes the channel status LED to flash.

The SLC processor reads the converted thermocouple or millivolt

data from the module at the end of the program scan, or when

commanded by the ladder program. After the processor and module

determine that the data transfer was made without error, the data can

be used in your ladder program.

Module Operation

The module’s input circuitry consists of eight differential analog

inputs, multiplexed into an A/D convertor. The A/D convertor reads

the analog input signals and converts them to a digital value. The

input circuitry also continuously samples the CJC sensors and

compensates for temperature changes at the cold junction (terminal

block).

Module Addressing

The module requires eight words each in the SLC processor’s input

and output image tables. Addresses for the module in slot e are as

follows:

I:e.0-7 thermocouple/mV or status data for channels 0-7,

respectively (dependent on bit in configuration word).

O:e.0-7 configuration data for channels 0-7, respectively.

See “Module Addressing” on page 3-1 to see the module’s image

table.

Module Overview 1-5

Publication 1746-6.22

Block Diagram

Terminal Block Module Circuitry

CJCA Sensor

Shield

CJCB Sensor

User Selected

Filter Frequency

Digital

Value

Analog to

Digi tal

Converter Digital

Filter

multiplexer

Analog

Ground

Within

12.5V

ungrounded

thermocouple

grounded

thermocouple

Important: When using multiple thermocouples, the potential

between any two cha nnels cannot excee d the channel -to-

channel differential voltage (12.5 volts). For more

information, see Appendix B.

1-6 Module Overview

Publication 1746-6.22

Linear Millivolt Device Compatibility

A large number of millivolt devices may be used with the 1746-NT8

module. For this reason we do not specify compatibility with any

particular device.

However, millivolt applications often use strain gage bridges. A

resist iv e volt age d ivider u sing f ixed resi stors i s rec ommende d for this

application. The circuit diagram below shows how this connection is

made.

Strain

Gage

Bridge

1746-NT8

fixed

variable

fixed

Voc

Channel

Input

Note: The resistors should be selected to ensure that the

differential input voltage is less than or equal to ±100

mV.

Publication 1746-6.22

Chapter

Installing And Wiring Your Module

Read this chapter to install and wire your modu le. This chapter

covers:

• avoiding electrostatic damage

• determining power requirements

• installing the module

• wiring signal cables to the module’s terminal block

Electrostatic Damage Electr ostat ic discha r ge can damag e semic onducto r de vices insid e t his

module if you touch backplane connector pins. Guard against

electrostatic damage by observing the following precautions:

ATTENTION: Electrostatically Sensitive

Components

• Before handling the module, touch a grounded

object to rid yourself of electrostatic charge.

• Han dle the modul e from the front, away from the

backplane connector. Do not touch backplane

connector pins.

• Keep the module in its static-shield container

when not in use or during shipment.

Failure to observe these precautions can degrade

the module’s performance or cause permanent

damage.

2-2 Installing And Wiring Your Module

Publication 1746-6.22

Power Requirements The module receives its power through the SLC 500 chassis

backplane from the fixed or modular +5 VDC/+24 VDC chassis

power supply. The maximum current drawn by the module is shown

in the table below.

Maximum Current Drawn by the Module

Considerations for a Modular System

Place your module in any slot of an SLC 500 modular, or modular

expansion chassis, except for the left-most slot (slot 0) reserved for

the SLC processor or adapter modules.

When using the modu le with a modul ar system, ad d t he val ues sho wn

above to the requirements of all other modules in the SLC to prevent

overloading the chassis power supply. Refer to the SLC 500 Modular

Hardware Style Ins tr uct io n and Operati ng Manual , publicat ion 1747-

6.2.

5VDC Amps 24VDC Amps

0.120 0.070

Installing And Wiring Your Module 2-3

Publication 1746-6.22

Fixed I/O Chassis - I/O Module Compatibility

The following chart depicts the range of current combinations

supported by the fixed I/O expansion chassis. To use it, find the

backplane curr ent dr aw and operat ing vo ltage for both mod ules being

used in the chassis. These specifications are found in the table

alongside the chart.

Next, plot each of the currents on the chart below. If the point of

intersection falls within the operating region, the combination is

valid. If not, the combination cannot be used in a 2-slot, fixed I/O

chassis.

Module Current Draw - Power Supply Loading

I/O Module 5V 24V I/O Module 5V 24V

BAS .150 .040 KE .150 .040

BASn .150 .125 KEn .150 .125

DCM .360 .000 NI4 .025 .085

FIO4I .055 .150 NI8 .200 .100

FIO4V .055 .120 NIO4I .055 .145

HS .300 .000 NIO4V .055 .115

HSTP1 .200 .000 NO4I .055 .195

IA4 .035 .000 NO4V .055 .145

IA8 .050 .000 NR4 .050 .050

IA16 .085 .000 NT4 .060 .040

IB8 .050 .000 OA16 .370 .000

IB16 .085 .000 OA8 .185 .000

IB32 .106 .000 OAP12 .370 .000

IC16 .085 .000 OB8 .135 .000

IG16 .140 .000 OB16 .280 .000

IH16 .085 .000 OB16E .135 .000

IM4 .035 .000 OB32 .452 .000

IM8 .050 .000 OBP8 .135 .000

IM16 .085 .000 OBP16 .250 .000

IN16 .085 .000 OG16 .180 .000

IO4 .030 .025 OV8 .135 .000

IO8 .060 .045 OV16 .270 .000

IO12 .090 .070 OV32 .452 .000

ITB16 .085 .000 OVP16 .250 .000

ITV16 .085 .000 OW16 .170 .180

IV8 .050 .000 OW4 .045 .045

IV16 .085 .000 OW8 .085 .090

IV32 .106 .000 OX8 .085 .090

Example: Plot IN16 and NIO4V

IN16 = 0.085 at 5V dc and 0A at 24V dc

NIO4V = 0.055A at 5V dc and 0.115A at 24V dc

1. Add current draws of both modules at 5V dc to get 0.14

(140mA)

2. Plot this point on the chart above (140mA at 5V dc).

3. Add current draws of both modules at 24V dc to get

0.115A (1 15mA)

4. Plot current draw at 24V dc (115mA at 24V dc)

5. Note the point of intersection on the chart above

(marked x). This combination falls within the valid

operating region for the fixed I/O chassis.

Important: The1746-NO4I and 1746-NO4V analog output

modules may require an external power supply.

100

150

200

250

300

350

400

450

100

150

200

at 5V dc

Current

(mA)

OA16 and

(0, 455)

OW16 and IA16

(180, 255)

Current (mA) at 24V

Plotted from

Example

Shown Below

Valid Operating

Region

2-4 Installing And Wiring Your Module

Publication 1746-6.22

When using the BAS or KE module to supply power to a 1747-AIC

Link Coupler, the link coupler draws its power through the module.

The higher current drawn by the AIC at 24V dc is shown in the table

as BASn (BAS networked) and KEn (KE networked). Be sure to use

these current draw values if the application uses the BAS or KE

module in this way.

General

Considerations Most applications require installation in an industrial enclosure to

reduce the effects of electrical interference. Thermocouple inputs are

highly susceptible to electrical noises due to the small amplitudes of

their signal (microvolt/°C).

Group your modules to minimize adverse effects from radiated

electrical noise and heat. Consider the following conditions when

selecting a slot for the thermocouple module. Position the module:

• in a slot away from sources of electrical noise such as hard-

contact switches, relays, and AC motor drives

• away from modules which generate significant radiated heat,

such as the 32-point I/O modules

In addition , route shielded twisted pair the rmocoup le or millivolt

input wiring away from any high voltage I/O wiring.

Remember that in a modular system, the processor or

communications adapter always occupies the first slot of the rack.

Installing And Wiring Your Module 2-5

Publication 1746-6.22

Module Installation

and Removal

To insert your module into the rack, follow these steps:

1. Before installing the module, connect the ground wire to TB1.

See figure on page 2-9.

2. Align the circuit board of your module with the card guides at

the top and bottom of the chassis.

3. Slide your module into the chassis until both top and bottom

retaining clips are secure. Apply firm even pressure on your

module to attach it to its backplane connector. Never force your

module into the slot.

4. Cover all unused slots with the Card Slot Filler, Allen-Bradley

part number 1746-N2.

ATTENTION: Possible Equipment Operation

Before installing or removing your module, always

disconnect power from the SLC 500 system and from

any other source to the module (in other words, do not

“hot swap” your module), and disconnect any devices

wired to the module.

Fail ure to observe this pre cau tion ca n cause uni ntende d

equipment operation and damage.

Top and Bottom

Module Release(s)

Card

Guide

2-6 Installing And Wiring Your Module

Publication 1746-6.22

Terminal Block Removal

To remove the terminal block:

1. Loosen the t wo termin al block relea se screws. To avoid cracking

the terminal block, alternate between screws as you remove

them.

2. Using a screwdriver or needle-nose pliers, carefully pry the

terminal block loose. When removing or installing the terminal

block be careful not to damage the CJC sensors.

Terminal block diagram with CJC sensors

Terminal Block

Release Screws

CJC Sensors

Terminal Block

Release Screws

Recommended Torque:

wiring screws: 0.25 Nm (2.2 in-lb)

release screws: 0.25 Nm (2.2 in-lb)

ATTENTION: Possible Equipment Operation

Before wiring your module, always disconnect power

from the SLC 500 system and from any other source to

the module.

Fail ure to observe this pre cau tion ca n cause uni ntende d

equipment operation and damage.

Installing And Wiring Your Module 2-7

Publication 1746-6.22

Wiring Your Module Follow these guidelines to wire your input signal cables:

• Power , input , and output ( I/O) wiring must be in acco rdance with

Class 1, Division 2 wiring methods [Article 501-4(b) of the

National Electrical Code, NFPA 70] and in accordance with the

authority having jurisdiction.

• Route thermocouple and millivolt signal wires as far as possible

from sources of electrical noise, such as motors, transformers,

contactors, and ac devices. As a general rule, allow at least 6 in.

(about 15.2 cm) of separation for every 120V ac of power.

• Routing the field wiring in a grounded conduit can reduce

electrical noise further.

• If th e fi eld wiri ng must c ross ac or p ower cabl es, ensur e th at they

cross at right angles.

• For high immunity to electrical noise, use Belden™ 8761

(shielded, twisted pair) or equivalent wire for millivolt sensors;

or use shielded, twisted pair thermocouple extension lead wire

specif ied by the t her mocouple man ufa cturer. Usi ng t he incor re ct

type of convention thermocouple extension wire or not

following the correct polarity may cause invalid readings.

• Ground the shield drain wire at only one end of the cable. The

preferred location is at the shield connections on the terminal

block. (Refer to IEEE Std. 518, Section 6.4.2.7 or contact your

sensor manufacturer for additional details.)

• Keep all unshielded wires as short as possible.

• Excessive tightening can strip a screw. Tighten screws to 0.25

Nm (2.2 in-lb) or less, based on UL 1059, CSA C22.2 No. 158,

VDE 0110B 2.79 standards.

• Follow system grounding and wiring guidelines found in your

SLC 500 Modular Installation and Operation Manual ,

publication 1747-6.2 (modular) or 1747-6.21 (fixed).

2-8 Installing And Wiring Your Module

Publication 1746-6.22

Preparing and Wiring the Cables

To prepare and connect cable leads and drain wires, follow these

steps:

1. At each end of the cable, strip some casing to expose individual

wires.

2. Trim signal wires to 5-inch lengths beyond the cable casing.

Strip a bout 3/ 16 inch (4 .76 mm) of insula ti on to expo se the end s

of the wires.

3. At the module end of the cables:

• extract the drain wire and signal wires

• remove the foil shield

• bundle the input cables with a cable strap

4. Connect pairs of drain wires together:

• Channels 0 and 1

• Channels 2 and 3

• Channels 4 and 5

• Channels 6 and 7

Keep drain wires as short as possible.

5. Connect the drain wires to the shield inpu ts of the term inal block

if appropriate for thermocouple used.

• Channel 0 and 1 drain wires to pin 5

• Channel 2 and 3 drain wires to pin 10

• Channel 4 and 5 drain wires to pin 15

• Channel 6 and 7 drain wires to pin 20

6. Connect the signal wires of each channel to the terminal block.

(Remove foil shield and drain wire

from sensor end of the cable.)

Cable

Signal Wires

Drain Wire

Signal Wires

Important: Only af ter verifying t hat your connections are correct fo r

each ch annel, trim t he le ngths to keep t hem shor t. Avoid

cutting leads too short.

Installing And Wiring Your Module 2-9

Publication 1746-6.22

7. Connect TB1 chassis ground connector to the nearest chassis

mounting bolt with 14 gauge wire. (Looking at the face of the

module, TB1 is near the lower part of the terminal block on the

primary side of the PCB.)

8. At the sensor end of cables from thermocouple/mV devices:

• remove the drain wire and foil shield

• apply shrink wrap as an option

• connect to mV devices keeping the leads short

TB1

Connect ground wire to TB1

before installing module.

Important: If noise persists, try grounding the opposite end of the

cable. Ground one end only.

2-10 Installing And Wiring Your Module

Publication 1746-6.22

Terminal Block Diagram with Input Cable

The module also has a ground terminal TB1, which should be

grounded to a chassis mounting bolt with 14-gauge wire.

Cold-Junction Compensation (CJC)

Thermocouple or mV Cable

CJC A+

CJC A-

CJC B-

CJC B+

Channel 0+

Channel 7-

Channel 7+

Channel 6-

Channel 6+

Channel 5-

Channel 5+

Channel 4-

Channel 4+

Channel 3-

Channel 3+

Channel 2-

Channel 2+

Channel 1-

Channel 1+

Channel 0-

Shield for CH0 and CH1

Shield for CH2 and CH3

Shield for CH4 and CH5

Shield for CH6 and CH7

TB1

Recommended Torque:

TB1 0.3 to 0.5 Nm (2.5 to 4.5 in-lb)

ATTENTION: Possible Equipment Operation

Do not remove or loosen the cold-junction

compensating temperature transducers located on the

terminal block. Both CJCs are required to ensure

accurate thermocouple input readings at each channel.

The module wi ll not oper at e i n the rmoc oupl e mode if a

CJC is not connected.

Fail ure to observe this pre cau tion ca n cause uni ntende d

equipment operation and damage.

Installing And Wiring Your Module 2-11

Publication 1746-6.22

To obtain accurate readings from each of the channels, the cold-

junction temperature (temperature at the module’s terminal junction

between the thermocouple wire and the input channel) must be

compensat ed f or. Two cold-ju nct ion compensa ti ng sensor s ha ve been

integrated in the removable terminal block. They must remain

installed.

Publication 1746-6.22

Chapter

Things To Consider Before Using

Your Module

This chapter explains how the module and the SLC processor

communicate through the processor’s I/O image tables. It also

describes the module’s input filter characteristics. Topics discussed

include:

• module ID code

• module addr essing

• channel filter frequency selection

• channel turn-on, turn-off, and reconfiguration times

• response to slot disabling

Modu le I D Code The module ID code is unique number assigned to each 1746 I/O

module. The ID code defines for the process or the type of I/ O module

and the number of words used in the processor’s I/O image table.

The module ID code for the 1746-NT8 module is 3533.

No special I/O configuration is required. The module ID

automatically assigns the correct number of input and output words.

3-2 Things To Consider Before Using Your Module

Publication 1746-6.22

Modu le Addressin g The following memory map shows you how the SLC processor’s

output and input tables are defined for the module.

Image Table

Output Image - Configuration Words

Eight words of the SLC processor’s output image table are reserved

for the module. Output image words 0-7 are used to configure the

module’s input channels 0-7. Each output image word configures a

single channel and can be referred to as a configuration word. Each

word has a unique address based on the slot number assigned to the

module.

Example Addr ess - If you want to co nfigure channe l 2 on the module

located in slot 4 in the SLC chassis, your address would be O:4.2.

Chapter 4, Channel Configuration, Data, and Status, gives you

detailed bit information about the data content of the configuration

word.

Channel 0 Configuration Word

Channel 1 Configuration Word

Channel 2 Configuration Word

Channel 3 Configuration Word

Channel 4 Configuration Word

Channel 5 Configuration Word

Channel 6 Configuration Word

Channel 7 Configuration Word

Channel 0 Data or Status Word

Channel 1 Data or Status Word

Channel 2 Data or Status Word

Channel 3 Data or Status Word

Channel 4 Data or Status Word

Channel 5 Data or Status Word

Channel 6 Data or Status Word

Channel 7 Data or Status Word

Output Ima ge

8 Words

Input Image

8 Words

SLC 5/0X

Data Files Output

Scan

Input

Scan

Slot e

Output Image

Input Image

Word 0

Word 1

Word 2

Word 3

Word 4

Word 5

Word 6

Word 7

O:e.0

O:e.1

O:e.2

O:e.3

O:e.4

O:e.5

O:e.6

O:e.7

Word 0

Word 1

Word 2

Word 3

Word 4

Word 5

Word 6

Word 7

I:e.0

I:e.1

I:e.2

I:e.3

I:e.4

I:e.5

I:e.6

I:e.7

Address

Bit 15

Bit 0

Thermocouple

Module

Image Table

O:4.2

Slot

Word

Delimiter

Element

Delimiter

File T y pe

Things To Consider Before Using Your Module 3-3

Publication 1746-6.22

Input Image - Data Words and Status Words

Eight wor ds of the SLC processor’ s input image table a re reserved for

the module. Input image words are multiplexed since each channel

has one data word and one status word. The corresponding

configur atio n word selec ts wheth er t he chan nel sta tu s or chan nel dat a

is in th e input image word.

Status bits for a particular channel reflect the configuration settings

that you entered into the configuratio n (outp ut ima ge) wor d for tha t

channel. To receive valid status, the channel must be enabled and the

module must have stored a valid configuration word for that channel.

Each inpu t image word has a uni que addre ss bas ed on the slot number

assigned to the module.

Example Address - To obtain the status/data word of channel 2

(input word 2) of the m odule locat ed in slot 4 in the SLC chassis u se

address I:4:2.

Chapter 4, Channel Configuration, Data, and Status, gives you

detailed bit information about the content of the data word and the

status word.

Channel Fi lter

Frequency Selection The thermocouple module uses a digital filter that provides high-

frequency noise rejectio n for the input signals. The dig ital fi lter is

programmabl e, a ll owi ng you to se le ct from fou r f il t er fr equencies for

each channel. The digit al filter provi de s the highest noi se rejecti on at

the selected filter frequency. The graphs to follow show the input

channel frequency response for each filter frequency selection.

Selecting a low value (i.e. 10 Hz) for the channel filter frequency

provides the best noise rejection for a channel, but it also increases

the channel update time. Selecting a high value for the channel filter

frequency provides lower noise rejection, but decreases the channel

update time.

The following tab le shows the availab le filter frequencie s, cut-off

frequency, s te p r esponse, and a DC effective re sol u ti on for each fi lter

frequency.

I:4.2

Slot

Word

Delimiter

Element

Delimiter

File Type

3-4 Things To Consider Before Using Your Module

Publication 1746-6.22

Cut-off frequency, Step Response Time, and Effective Resolution (Based on Filter

Frequency)

The step response is calculated by a 4 x (1/filter frequency) settling

time.

Channel Cut-Off Frequency

The channel filter frequency selection determines a channel’s cut-off

frequency, also called the -3 dB frequency. The cut-off frequency is

defined as the point on the input channel frequency response curve

where fr equency component s of th e input signa l are p assed wi th 3 dB

of attenuation. All frequency components at or below the cut-off

frequency are passed by the digital filter with less than 3 dB of

attenuation. All frequency components above the cut-off frequency

are increasingly attenuated, as shown in the graphs on page 3-5.

The cut-off frequency for each input channel is defined by its filter

frequency selection. The table above shows the input channel cut-off

frequency for each filter freque ncy. C hoose a filter freq uency so that

your fastest changing signal is below that of the filter’s cut-off

frequency. The cut-off frequency should not be confused with update

time. The cut-off frequency relates how the digital filter attenuates

frequency components of the input signal. The update time defines

the rate at which an input channel is scanned and its channel data

word updated.

Filter Frequency Cut-Off Frequency Step Response ADC Effe ctive

Resolution

10 Hz 2.62 Hz 400 ms 20.5

50 Hz 13.1 Hz 80 ms 19.0

60 Hz 15.72 Hz 66.7 ms 19.0

250 Hz 65.5 Hz 16 ms 15.5

Things To Consider Before Using Your Module 3-5

Publication 1746-6.22

Signal Attenuation with 10 Hz Input Filter

Signal Attenuation with 50 Hz Input Filter

-20

-40

-60

-80

-100

-120

-140

-160

-180

-2000

2.62 Hz Signal Frequency

-3 dB

10 20 30 40 50 60 Hz

Amplitude (in dB)

-20

-40

-60

-80

-100

-120

-140

-160

-180

-2000 50 100 150 200 250 300 Hz

13.1 Hz

-3 dB

Amplitude (in dB)

Signal Frequency

3-6 Things To Consider Before Using Your Module

Publication 1746-6.22

Signal Attenuation with 60 Hz Input Filter

Signal Attenuation with 250 Hz Input Filter

Channel Step Response

The channel filter frequency determines the channel’s step response.

The step r es ponse i s time requir ed for th e anal og input signa l to reac h

95% of its expected, final value given a full-scale step change in the

input s ignal . This me ans th at if an i nput si gnal changes fast er t han the

channel step response, a portion of that signal will be attenuated by

the channel filter. The table on page 3-5 shows the step response for

each filter freque ncy.

-20

-40

-60

-80

-100

-120

-140

-160

-180

-2000 60 120 180 240 300 360 Hz

-3 dB

15.7 Hz Signal Frequency

Amplitude (in dB)

-20

-40

-60

-80

-100

-120

-140

-160

-180

-2000 250 500 750 1000 1250 1500 Hz

-3 dB

Amplitude (in dB)

Signal Frequency

65.5 Hz

Things To Consider Before Using Your Module 3-7

Publication 1746-6.22

Update Time The th ermocoupl e module update ti me is def in ed as th e time r equir ed

for the module to sample and convert the input signals of all enabled

input channels and make the resulting data values available to the

SLC processor. It can be calculated by adding the sum of all enabled

sample times, plus a CJC update time.

The following table shows the channel sampling time for each filter

frequency. It also gives the CJC update time.

Channel Sa mpling Time

The times above include a settling time necessary between input

channel readings. The sampling times for filter frequencies listed do

not include a 45 msec open-circuit detection time utilized when the

channel is configured for open-circuit detection. CJC open-circuit

detection does not require the additional 45 msec settling time.

The fastest module update time occurs when only one channel with a

250 Hz filter frequency is enabled.

Module update time = 290 msec + 66 msec = 356 msec

The slowest module update time occurs when eight channels, each

using a 10 Hz filter frequency, are enabled.

Module update time = 290 msec + 470 msec + 470 msec + 470

msec + 470 msec + 470 msec + 470 msec + 470 msec + 470

msec = 4.05 sec

Update Time Calculation Example

The following example shows how to calculate the module update

time for the given configuration:

Channel 0 configured for 250 Hz filter frequency, enabled

Channel 1 configured for 250 Hz filter frequency, enabled

Channel 2 configured for 50 Hz filter frequency, enabled

Channel 3 through 7 disabled

Sample

Channel 0 Sample

Channel 1 Sample

Channel 2 Sample

Channel 7 Sample

CJC

Channel

Enabled Enabled Enabled Enabled

Channel 0 Disabled Channel 1 Disabled Channel 2 Disabled Channel 7 Disabled

Update CJC Calculate

Previous Calculate

Channel Sampling Time for Each Filter Frequency (all values ±1 msec)

Channel Sampling Time

CJC Update Time 250 Hz Filter 60 Hz Filter 50 Hz Filter 10 Hz Filter

290 msec 66 msec 125 msec 140 msec 470 msec

3-8 Things To Consider Before Using Your Module

Publication 1746-6.22

Using the values from the table on page 3-7, add the sum of all

enabled channel sample times, plus one CJC update time.

Channel Tur n-On,

Turn-Off, and

Reconfiguration Times

The time required for the module to recognize a new configuration

for a channel is generally one module update time plus 890 µsec per

newly configured channel. If the filter frequency selected for the

newly enabled, configured channel is new to the module, then auto-

calibration is performed following configuration recognition.

Turn-off time requires up to one module update time.

Reconfiguration time is the same as turn-on time.

Auto-Calibration Auto-calibration is performed by the module to correct for drift errors

over tempe rature. Auto- calibra tion occurs immediat el y following

configuration of a previously unselected filter frequency, and

generally every tw o minutes for a ll selected filter frequencies of the

system. The time required to perform auto-calibration is defined as

follows:

Auto-calibration Time

CJC sensor s are acquire d at 60 Hz to maximize t he trade-of fs between

resolution and update rate. For example, if some channels are

acquired at 250 Hz and some are acquired at 50 Hz, then the total

auto-calibration time would be:

During auto-calibration, input values are not updated.

Channel 0 sampling time = 66 msec

Channel 1 sampling time = 66 msec

Channel 2 sampling time = 140 msec

CJC update time = 290 msec

Module update time = 562 msec

250 Hz Filter 60 Hz Filter 50 Hz Filter 10 Hz Filter

325 msec 525 msec 585 msec 1.975 s

Frequency Auto-Calibration

250 Hz 325 msec

60 Hz 525 msec

50 Hz 585 msec

1.435 sec Total

Things To Consider Before Using Your Module 3-9

Publication 1746-6.22

Response to Slot

Disabling By writing to the status file in the modular SLC processor, you can

disable any chassis slot. Refer to your SLC programming manual for

the slot disable/enable procedure.

Input Response

When a thermocou p le slot is dis abl ed, the ther mocouple modul e

continues to update its input image table. However, the SLC

processor does not read input from a module that is disabled.

Therefore, when the processor disab les the thermocouple module slot,

the module inputs appearing in the processor image table remain in

their last state, and the module’s updated image table is not read.

When the processor re-enables the module slot, the current state of

the module inputs are read by the processor during the subsequent

scan.

Output Response

The SLC pr ocessor ma y change t he ther mocouple module out put data

(confi guration) as it appear s in the pr ocessor output image . Howeve r,

this data is not transferred to the thermocouple module. The outputs

are held in their last state. When the slot is re-enabled, the data in the

processor image is transferred to the thermocoup l e mod ule.

ATTENTION: POSSIBLE EQUIPMENT

OPERATION

Always understand the implications of disabling a

module before using the slot disable feature.

Fail ure to observe this pre cau tion ca n cause uni ntende d

equipment operation.

Publication 1746-6.22

Chapter

Channel Configuration, Data, and

Status

Read this chapter to:

• configure each input channel

• check each input channel’s configuration and status

Channel Configuration Channel configuration words appear in the SLC processor’s output

image table as shown below. Words 0-7 correspond to module

channels 0-7.

After module installation, configure each channel to establish the way

the channel operates (e.g., thermocouple type, temperature units,

etc.). Configure the channel by setting bits in the configuration word

using your programming device. The SLC configuration words are

shown below.

SLC Output Image (Configuration) Words

e = slot number of the module

O:e.0

O:e.1

O:e.2

O:e.3

O:e.4

O:e.5

O:e.6

O:e.7

Channel 0 Channel Configuration Word

Channel 1 Channel Configuration Word

Channel 2 Channel Configuration Word

Channel 3 Channel Configuration Word

Channel 4 Channel Configuration Word

Channel 5 Channel Configuration Word

Channel 6 Channel Configuration Word

Channel 7 Channel Configuration Word

4-2 Channel Configuration, Data, and Status

Publication 1746-6.22

The configuration word default settings are all zero. Next, we

describe how you set configuration bits of a channel configuration

word to set up the followin g channel pa rameters:

• data format such as engineering units, counts, or scaled for PID

• how the channel should respond to a detected open-input circuit

• filter frequency selection

• tem perature units in °C or °F

• whether the channel is enabled or disabled

• whether status or data information is selected for the module’s

input image table.

Channel Configuration

Procedure The channel configuration word consists of bit fields, the settings of

which determine how the channel operates. This procedure looks at

each bit field separately and helps configure a channel for operation.

Refer to the chart on page 4-4 and the bit field descriptions that

follow for complete configuration information.

1. Determine which channels are used in your program and enable

them. Place a one in bit 0 if the channel is to be enabled. Place a

zero in bit 0 if the channel is to be disabled.

2. Determine the input device type (J, K, etc. thermocouple) (or

mV) for a channel and ente r its re spective four -digit binary code

in bit field 1 through 4 of the channel configuration word.

3. Sele ct a data f ormat for t he data word. Your selectio n deter mines

how the analog input value from the A/D converter will be

expressed in the data word. Enter your two-digit binary code in

bit field 5 and 6 of the channel configuration word.

4. Determine the desired state for the channel data word if an open-

circuit condition is enabled and detected for that channel. Enter

the two-digit binary code in bit field 7 and 8 of the channel

configuration word.

5. If the channel is configured for thermocouple inputs, determine

if the channel data word should read in degrees Fahrenheit or

degrees Celsius and enter a one or a zero in bit 9 of the

configur ation word . If the chan nel is configu red for a mV anal og

sensor, enter a zero in bit 9.

6. Determine the desired input filter frequency for the channel and

enter the two-digit binary code in bits 10 and 11 of the channel

configuration word. A lower filter frequency increases the

channel update time, but also increases the noise rejection and

channel resolution. A higher filter frequency decreases the

channel update time, but also decreases the noise rejection and

effective resolution.

Channel Configuration, Data, and Status 4-3

Publication 1746-6.22

7. Ensure that bits 12 through 14 contain zeros.

8. Determine whether t he channel input ima ge word shoul d contai n

data or status. Place a one in bit 15 if channel data is desired.

Place a zero in bit 15 if status is desired.

9. Build the channel configuration word for every channel on each

thermocouple/mV module repeating the procedures given in

steps 1 through 8.

10. Enter this configuration into your ladder program and download

it to the thermocouple module.

4-4 Channel Configuration, Data, and Status

Publication 1746-6.22

A detailed explanation appears in the following table:

Channel Configuration Word (O:e.0 through O:e.7) - Bit Definitions

Channel

Enable

1514131211109876543210

Channel D i sa ble

Channel E nable 0

Input

Type

Thermocouple Type J 0000

Thermocouple Type K 0001

Thermocouple Type T 0010

Thermocouple TypeE 0011

Thermocouple Type R 0100

Thermocouple TypeS 0101

Thermocouple Type B 0110

Thermocouple Type N 0111

±50 mV 1000

±100 mV 1001

Invalid 1 0 1 0

Invalid 1 0 1 1

Invalid 1 1 0 0

Invalid 1 1 0 1

Invalid 1 1 1 0

CJC temperature 1111

Data

Format

Engineering Units x 1100

Engineering Units x 10101

Scaled for PID 10

Proportional counts 11

Open Circuit

Zero on open circuit 00

Max. on open circuit 01

Min. on open circuit 10

Disabled 11

Temperature

Units Degrees C20

Degrees F21

Channel

filter

freq.

10 Hz input filter 00

50 Hz input filter 01

60 Hz input filter 10

250 Hz input filter 11

Unused Unused3000

Invalid 1 1 1

Input Image

Type Status Word 0

Data Word 1

1. For engineering units x1, values are expressed in 0.1 degrees or 0.01 mV. For engineering units x10, values are expressed in 1.0 degree or 0.1 mV.

2. When millivolt input type is selected, the bit setting for temperature units is ignored.

3. Ensure unused bits 12 through 14 are always set to zero.

Channel Configuration, Data, and Status 4-5

Publication 1746-6.22

Select Channel Enable (Bit 0)

Use the channel enable bit to enable a channel. The thermocouple

module only scans enabled channels. To optimize module operation

and minimize throughput times, unused channels should be disabled

by setting the channel enable bit to zero (default value).

When set (1) the channel enable bit is used by the module to read the

configuration word information selected. While the enable bit is set,

modification of the configuration word may lengthen the module

update time for one cycle. If any change is made to the configuration

word , the change is reflected in the status word before new data is

valid (described on page 4-11).

While the channel enable bit is cleared (0), the associated channel

data/s tat us word va lues ar e clea red . After t he c hannel e nable bi t is se t

(1), the associated channel data/status word remains cleared until the

thermocou ple module s et s t he cha nnel stat us bi t ( bi t 0 ) i n t he channel

status word.

Select Input Types (Bits 1 through 4)

The input type bit field lets you configure the channel for the type of

input device you have connected to the module. Valid input devices

are type s J, K, T, E, R, S, B, and N thermocou ple sensors an d ±50 mV

and ±100mV analog input signals. The channel can also be

configured to read the cold-junction temperature calculated for that

specific channel. When the cold-junction compensation (CJC)

temperature is selected, the channel ignores the physical input signal.

Select Data Format (Bits 5 and 6)

The d ata format bit field le ts you d efine the exp ressed format for the

channel data word contained in the module input image. The data

types are engineering units, scaled-for-PID, and proportional counts.

The enginee ring units all ow you to selec t from two resoluti ons, x1 or

x10. For engineering units x1, values are expressed in 0.1 degrees or

0.01mV. For engineering units x10, values are expressed in 1.0

degrees or 0.1mV. (Use the x10 setting to produce temperature

readings in whole degrees Celsius or Fahrenheit.)

The scaled-for-PID value is the same for millivolt, thermocouple,

and CJC input types. The input signal range is proportional to your

select ed i nput t ype and scale d in to a 0 t hrough 16,38 3 range, which i s

standard to the SLC PID algorithm.

The proportional counts are scaled to fit the defined temperature or

voltage range. The input signal range is proportional to your selected

input and scaled into a -32,768 to 32,767 range.

4-6 Channel Configuration, Data, and Status

Publication 1746-6.22

Using Scaled-for-PID and Proportional Counts

The ther mocouple module provi des ei ght o ptions for displ aying input

channel data. These are 0.1°F, 0.1°C, 1°F, 1°C, 0.01 mV, 0.1 mV,

Scaled-for-PID, and Proportional Counts. The first six options

represent real Engineering Units displayed by the 1746-NT8 and do

not requ ire expl ana ti on. Th e Scaled- for-PID and Proportional Cou nts

select ions provi de the highe st NT8 displa y resolutio n, but als o require

you to manually convert the channel data to real Engineering Units.

The equations below show how to convert from Scaled-for-PID to

Engineering Units, Engineer ing Units to Scaled-for -PID, Proportional

Counts to Engineering Units, and Engineering Units to Proportional

Counts. To perform the conversions, use the defined temperature or

millivolt range for the channel’s input type. See the Channel Data

Word Format table on page 4-7. The lowest possible value for an

input type is SLOW, and the highest possible value is SHIGH.

Effective Resolutions

The effective resolution for an input channel depends upon the filter

frequency selected for that channel.

Channel Configuration, Data, and Status 4-7

Publication 1746-6.22

Scaling Examples

Scaled-for-PID to Engineering Units

Equation: Engineering Units Equivalent = SLOW + [(SHIGH-SLOW) x (Scaled-for-PID value displayed/16384)]

Assume type J input type, scaled-for-PID display type, channel data = 3421.

Want to calculate °C equivalent.

From Channel Data Word Format table, SLOW = -210°C and SHIGH = 760°C.

Solution: Engineering Units Equivalent = -210°C + [(760°C-(-210°C)) x (3421/16384)] = -7.46°C.

Engineering Units to Scaled-for-PID

Equation: Scaled-for-PID Equivalent = 16384 x [(Engineering Units desired -SLOW)/(SHIGH-SLOW)]

Assume type J input type, scaled-for-PID display type, desired channel temp. = 344°C.

Want to calculate Scaled-for-PID equivalent.

From Channel Data Word Format table, SLOW = -210°C and SHIGH = 760°C.

Solution: Scaled-for-PID Equivalent = 16384 x [(344°C - (-210°C))/(760°C - (-210°C))] = 9357

Proportion al Co unts to Engineering Units

Equation: Engineering Units Equivalent = SLOW + {(SHIGH-SLOW) x [(Proportional Counts value displayed + 32768)/

65536]}

Assume type E input type, proportional counts display type, channel data = 21567.

Want to calculate °F equivalent.

From Channel Data Word Format table, SLOW = -454°F and SHIGH =1832°F

Solution: Engineering Units Equivalent = -454°F + {[1832°F -(-454°F)] x [(21567 + 32768)/65536]} = 1441.3°F

Engineering Units to Proportional Counts

Equation: Proportional Counts Equivalent = {65536 x[(Engineering Units desired - SLOW)/(SHIGH-SLOW)]} -32768

Assume type E input type, proportional counts display type, desired channel temp. = 1000°F.

Want to calculate Proportional Counts equivalent.

From Channel Data Word Format table, SLOW = -454°F and SHIGH = 1832°F.

Solution: Proportional Counts Equivalent = {65536 x[{1000°F - (-454°F))/(1832°F - (-454°F))]} - 32768 = 8916.

4-8 Channel Configuration, Data, and Status

Publication 1746-6.22

1746-NT8 Thermocouple Module - Channel Data Word Format

Data Format

Input

Type

Engineering Units x10 Engineering Units x1 Scaled-for-

PID Proportional

Counts

° Celsius ° Fahrenheit ° Celsius ° Fahrenheit

J -210 to +760 -346 to +1400 -2100 to +7600 -3460 to +14000 0 to +16383 -32768 to +32767

K -270 to +1370 -454 to +2498 -2700 to +13700 -4540 to +24980 0 to +16383 -32768 to +32767

T -270 to +400 -454 to +752 -2700 to +4000 -4540 to +7520 0 to +16383 -32768 to +32767

E -270 to +1000 -454 to +1832 -2700 to +10000 -4540 to +18320 0 to +16383 -32768 to +32767

R 0 to +1768 +32 to +3214 0 to +17680 +320 to+32140 0 to +16383 -32768 to +32767

S 0 to +1768 +32 to +2372 0 to +17680 +320 to +32140 0 to +16383 -32768 to +32767

B +300 to +1820 +572 to +3308 +3000 to +18200 +5720 to +3276.710 to +16383 -32768 to +32767

N 0 to +1300 +32 to +2372 0 to +13000 +320 to +23720 0 to +16383 -32768 to +32767

±50 mV2-500 to +500 -500 to +500 -5000 to +5000 -5000 to +5000 0 to +16383 -32768 to +32767

±100 mV2-1000 to +1000 -1000 to +1000 -10000 to +1000 -10000 to +10000 0 to +16383 -32768 to +32767

CJC Sensor -25 to +105 -13 to +221 -250 to +1050 -130 to +2210 0 to +16383 -32768 to +32767

1. Type B thermocouple cannot be represented in engineering units x1 (°F) above 3276.7°F. Software treats it as over range error.

2. When millivolts are selected, the temperature setting is ignored. Analog input data is the same for either °C or °F selection.

Channel Configuration, Data, and Status 4-9

Publication 1746-6.22

1746-NT8 Thermocouple Module - Channel Data Word Resolution

Select Open-Circuit State (Bits 7 and 8)

The open-circuit bit field lets you define the state of the channel data

word when an open-circuit condition is detected for that channel. This

feature can be disabled by selecting the disable option.

An open-circuit condition occurs when the thermocouple itself or its

extensi on wire i s physi cally separa ted or op en. This ca n happen i f the

wire gets cut or disconnected from terminal block.

If either of the two CJC devices is removed from the terminal block,

any input channel configured for either a thermocouple or CJC

temperature input is placed in an open-circuit condition. An input

channel configured for millivolt input is not affected by CJC open-

circuit conditions.

The res ult s of the d at a word in an ope n-cir cuit condi tion depe nd upon

the selection of bits 7 and 8.

If zero is selec ted (00 ), the ch anne l data word i s forc ed to 0 dur in g an

open-circuit condition.

Data Format

Input

Type

Engineering Units x 10 Engineering Units x 1 Scaled-for-PID Proportional Counts

° Celsius ° Fahrenheit ° Celsius ° Fahrenheit ° Celsius ° Fahrenheit ° Celsius ° Fahrenheit

J1°C/step 1°F/step 1°C/step 1°F/step 0.0592°C/step 0.1066°F/step 0.0148°C/step 0.0266°F/step

K 1°C/step 1°F/step 1°C/step 1°F/step 0.1001°C/step 0.1802°F/step 0.0250°C/step 0.0450°F/step

T 1°C/step 1°F/step 1°C/step 1°F/step 0.0409°C/step 0.0736°F/step 0.0102°C/step 0.0184°F/step

E 1°C/step 1°F/step 1°C/step 1°F/step 0.0775°C/step 0.1395°F/step 0.0194°C/step 0.0349°F/step

R 1°C/step 1°F/step 1°C/step 1°F/step 0.1079°C/step 0.1942°F/step 0.0270°C/step 0.0486°F/step

S 1°C/step 1°F/step 1°C/step 1°F/step 0.1079°C/step 0.1942°F/step 0.0270°C/step 0.0486°F/step

B 1°C/step 1°F/step 1°C/step 1°F/step 0.0928°C/step 0.1670°F/step 0.0232°C/step 0.0417°F/step

N 1°C/step 1°F/step 1°C/step 1°F/step 0.0793°C/step 0.1428°F/step 0.0198°C/step 0.0357°F/step

±50 mV10.1mV/step 0.1mV/step 0.01mV/step 0.01mV/step 6.104µV/step 6.104µV/step 1.526µV/step 1.526µV/step

±100 mV10.1mV/step 0.1mV/step 0.01mV/step 0.01mV/step 12.21µV/step 12.21µV/step 3.052µV/step 3.052µV/step

CJC Sensor 1°C/step 1°F/step 1°C/step 1°F/step 0.0079°C/step 0.0143°F/step 0.0020°C/step 0.0036°F/step

1. When millivolts are selected, the temperature setting is ignored. Analog input data is the same for either °C or °F selection.

Important: Data resolution is not equivalent to data accuracy. Input

accura cy of ±50 µV may span mult iple steps f or PID and

Proportional Counts data types. As an example, a Type

B thermocouple temperature range of 0 to 1820°C

provides a voltage input range of 0 to 13.82mV to the

1746-NT8. This is a ve ry small i nput range and , when it

is scaled to PID or proportional counts ranges, a small

input change results in many counts being changed.

4-10 Channel Configuration, Data, and Status

Publication 1746-6.22

Selecting maximum forces the (01) channel data word value to its

full scale value during an open-circuit condition. The full scale value

is determined by the selected input type and d ata format.

Selecting minimum forces the (10) channel data word v alue to its

low scale value dur ing an ope n-cir cuit co nditi on. The low sc ale val ue

is determined by the selected input type and d ata format.

Disabling the open-circuit selection (11) may result in unintended

operation on a failur e. Gen erally, with the open-circuit option

disable d, the data word remains u nchanged. The o pen-circ uit error bit

and the channel LED flags the condition until the error is resolved.

For example, if channel one is configured as a thermocouple type

when the CJC breaks in an open-circuit condition, if open-circuit

detection is disabled, the data word remains unchanged. If the circuit

select ion is set at mini mum, th e data wo rd is set to the low s cale valu e

for the range and format.

Select Temperature Units (Bit 9)

The temperature units bit lets you select temperature engineering

units for thermocouple and CJC input types. Units are either degrees

Celsius (°C) or degrees Fahrenheit (°F). This bit field is only active

for thermocouple and CJC input types. It is ignored when millivolt

inputs types are selected.

Select Channel Filter Frequency (Bits 10 and 11)

The chann el f ilte r freque ncy bit fiel d lets you selec t one of f our fil ters

available for a channel. The filter frequency affects the channel

update time and noise reje ction charac teristics. A smaller filter

frequency increases the channel update time, but also increases the

noise rejectio n and channel resolution. A la rger filt er freq uency

decreases the noise rejection, but also decreases the channel update

time an d channel res olution. Gui del ines for filter fre quency are li st ed

below.

Important: Enab ling the open-circuit function adds approximately

45 msec to the channel update time. Disabling the open-

circuit detection removes the time adder . CJC sensors do

not require the additional time; thus it is recommended

that when using a channel for CJC sensor acquisiti on,

the open-circuit selection is enabled.

Important: If you are using engineering units (x1 mode) and

Fahrenheit temperature units (i.e. 0.1°F), the full scale

temperature for thermocouple type B is not achievable

with 16-bit signed numerical representation. An over-

rang e er ror occurs for th at channel if it tri es to re present

the full scale value. The maximum representable

temperature is 3276.7°F (instead of 3308°F).

Channel Configuration, Data, and Status 4-11

Publication 1746-6.22

• 250 Hz setting provides minimal noise filtering.

• 60 Hz setting provides 60 Hz AC line noise filtering.

• 50 Hz setting provides 50 Hz AC line noise filtering.

• 10 Hz setting provides both 50 Hz and 60 Hz AC line noise

filtering.

When a CJC input type is selected, filter frequency is ignored. To

maximize the speed versus resolution trade-off, CJC inputs are

sampled at 60 Hz.

Unused Bits (Bits 12 through 14)

Bits 12-14 are not defined. Ensure these bits are always cleared (0).

Select Input Image Type (Bit 15)

The input image type bit allows you to select data or status

information in the channel’s input image word. When set (1), the

module places channel data in the corresponding input image word.

When the bit is cleared (0) the module places channel status in the

corresponding input image word.

4-12 Channel Configuration, Data, and Status

Publication 1746-6.22

Channel Data/Status

Word The actual thermocouple or millivolt input data values or channel

status reside in I:e.0 through I:e.7 of the thermocouple module input

image file. The data values present depend on the input type and data

formats you have s elected. When an inpu t chan nel is disa bled, it s data

word is reset (0).

Channel Status

Checking You can use the informat ion provided in the stat us wor d to d ete rmine

if the input configuration data for any channel is valid per your

configuration in O:e.0 through O:e.7.

The channel status can be analyzed bit by bi t. In additi on to providi ng

info rmat io n about an enabled or di sabled channel, ea ch bit’s sta tus (0

or 1) tells you how the input data from the thermocouple or millivolt

analog sensor connected to a specific channel will be translated for

your application. The bit status also informs you of any error

condition and can tell you what type of error occurred.

A bit-by -bit exa mination o f the stat us word is provided in the chart o n

the following page.

Channel 0 Channel Data/Status Word

Channel 1 Channel Data/Status Word

Channel 2 Channel Data/Status Word

Channel 3 Channel Data/Status Word

Channel 4 Channel Data/Status Word

Channel 5 Channel Data/Status Word

Channel 6 Channel Data/Status Word

Channel 7 Channel Data/Status Word

Module Input Image (Data/Status) Word

I:e.0

I:e.1

I:e.2

I:e.3

I:e.4

I:e.5

I:e.6

I:e.7

Channel Configuration, Data, and Status 4-13

Publication 1746-6.22

Channel 0-7 Status Word (I:e.0 through I:e.7) - Bit Definitions

1514131211109876543210

Channel

Status Channel Disable

Channel Enable 0

Input

Type

Thermocouple Type J 0000

Thermocouple Type K 0001

Thermocouple Type T 0010

Thermocouple TypeE 0011

Thermocouple Type R 0100

Thermocouple TypeS 0101

Thermocouple Type B 0110

Thermocouple Type N 0111

±50 mV 1000

±100 mV 1001

Invalid 1 0 1 0

Invalid 1 0 1 1

Invalid 1 1 0 0

Invalid 1 1 0 1

Invalid 1 1 1 0

CJC temperature 1111

Data

Format

Engineering Units x 1 00

Engineering Units x 10 01

Scaled for PID 10

Proportional counts 11

Open

Circuit

Zero on open circuit 00

Max. on open circuit 01

Min. on open circuit 10

Disabled 11

Temperature

Units Degrees C 0

Degrees F 1

Channel

filter

frequency

10 Hz input filter 00

50 Hz input filter 01

60 Hz input filter 10

250 Hz input filter 11

Open-circuit

error No error 0

Open circuit detected 1

Under-range

error No error 0

Under range condition 1

Over-range

error No error 0

Over range condition 1

Channel

error No error 0

Channel error 1

Note: It takes one timing cycle to complete an update. (Refer

to Chapter 3 for module update times.)

4-14 Channel Configuration, Data, and Status

Publication 1746-6.22

Explanations of the status conditions follow.

Channel Status (Bit 0)

The channel status bit indicates operational state of the channel.

When the ch annel en able bit is set in the configuratio n word , the

thermocouple module configures the selected channel and takes a

data sample for the channel data word before setting this bit in the

status word.

Input Type Status (Bits 1 through 4)

The input type bit field indicates what type of input signal you have

configured for the channel. This field reflects the input type defined

in the channel configuration wor d.

Data Format Type Status (Bits 5 and 6)

The data format bit field indicates the data format you have defined

for the channel. This field reflects the data type selected in bits 5 and

6 of the channel configuration word.

Open-Circuit Type Status (Bits 7 and 8)

The open-circuit bit field indicates how you have defined the open-

circuit bits configuration word, and therefore, the response of the

thermocouple module to an open-circuit condition. This feature is

active for all input types, including CJC temperature input.

Temperature Units Ty pe Status (Bit 9)

The temper ature u nits field i ndicates the sta te of t he temp erature units

bit in the configuration word (bit 9).

Channel Filter Frequency (Bits 10 and 11)

The channel filter frequency bit field reflects the filter frequency you

selected in the configuration word.

Open-Circuit Error (Bit 12)

This bit is set (1) whenever a configured channel detects an open-

circuit condition at its input. An open-circuit at the CJC sensor also

flags t his e rror if the chan nel input type is either thermoc ouple or CJC

temperature. A range error on the CJC sensor also flags this bit if the

input type is thermocouple.

Important: If the channel for which you are seeking status is

disabled, all bit fields are cleared. The status word for

any disabled channel is always 0000 0000 0000 0000

regardless of any previous setting that may have been

made to the configuration word.

Channel Configuration, Data, and Status 4-15

Publication 1746-6.22

Under-Range Error (Bit 13)

This bit is set (1) whenever a configured channel detects an under-

range condi tion fo r the channel da ta. An under -ran ge cond ition exists

when the input value is equal to or below the specified lower limit of

the particular sensor connected to that channel.

Over-Range Error (Bit 14)

This bit is set (1) whenever a configured channel detects an over-

range condition for the channel data. An over-range condition exists

when the input value is equal to or above the specified upper limit of

the particular sensor connected to that channel.

Channel Error (Bit 15)

This bit is set (1) whenever a configured channel detects an error in

the configuration word, or an error has occurred while acquiring the

A/D data value. If during the auto-calibration process, the module

detects an out-of-range condition for the filter frequency selected for

the channel, the channel error bit is set. An out-of-range condition

occurring during auto-calibration would be the result of an overly

noisy environment, whereby the module cannot maintain accuracy

specif ications, thu s flagging a n error . The er ror bit is cle ared when the

error condition is resolved. The channel data word is not updated

during a period of auto-calibration filter frequency tolerance errors.

Publication 1746-6.22

Chapter

Programming Examples

Earlier chapters explained how the configuration word defines the

way a channel operates. This chapter shows the programming

required to configure the module. It also provides you with segments

of ladder logic specific to unique situations that might apply to your

programming requirements. The example segments include:

• basic example

• automatic monitoring thermocouples and CJC sensors

• verifying channel configuration changes

• interfa cing to the PID instruction

• monitoring channel status bits

• PLC 5 example with NT8 in remote I/O rack

Basic Example To enter data into the channel configuration word (O:e.0 through

O:e.7) when the channel is disabled (bit 0 = 0), follow these steps.

Refer to the table on page 4-4 for specific configuration details.

Example - Configure eight channels of a thermocouple module

residing in slot 3 of 1746 chassis. Configure each channel with the

same parameters.

Channel Configuration

The following procedure transfers configuration data and sets the

channel enable bits of all eight channels with a single File Copy

instruction.

1 1

00 100 01 0001

15 14 13 12 11 10

87 65 4321

000

Configure Channel for:

Channel Enable Bit

Type K Thermocouple Inpu

Engineering Units X 10

Zero if Open Circuit

Fahrenheit

10 Hz Filter Frequency

Not Used

Data Word

5-2 Programming Examples

Publication 1746-6.22

Procedure

1. Create integer file N10. Integer file N10 should contain eight

elements (N10:0 through N10:7).

2. Using the programming software, enter the configuration

parameters for all eight thermocouple channels into data file

locations N10:0 through N10:7.

Data table for initial programming

3. Program a rung in your ladder logic to copy the contents of

integer file N10 to the eight consecutive output words of the

thermocouple module beginning with O:3.0.

Initial programming example

On power up, bit S:1/15 is set for the first program scan. During the

first program scan, the configuration data in N10:0 through N10:7

will be sent to the 1746-NT8 channel configuration words.

address 15 data 0 address 15 data 0

N10:0 1000 0010 0010 0011

N10:1 1000 0010 0010 0011

N10:2 1000 0010 0010 0011

N10:3 1000 0010 0010 0011

N10:4 1000 0010 0010 0011

N10:5 1000 0010 0010 0011

N10:6 1000 0010 0010 0011

N10:7 1000 0010 0010 0011

Press a key or enter value

N10:3/0 = 1

offline no forces binary data decimal addr File EXMPL

CHANGE SPECIFY NEXT PREV

RADIX ADDRESS FILE FILE

F1 F5 F7 F8

S:1

COP

Copy File

Source #N10:0

Dest #O:3.0

Length 8

COP

#NT8_CONFIGURATION

END

During the first pass, send the channel configuration data to the thermocouple module.

First Pass

0000

0001

Programming Examples 5-3

Publication 1746-6.22

Automatic Monitoring

Thermocouples and

CJC Sensors

The following example explains how to change data in the channel

configuration word when the channel is currently enabled.

Example - Execute a dynamic configuration change to channel 0 of

the thermocouple module located in slot 1 of a 1746 chassis.

Periodically (e.g., every 60 seconds) change from monitoring an

externa l type K thermoco uple to monitorin g the CJC sensors mounted

on the terminal block. The CJC reading gives a good indication of

what the t emperature is insi de the cont rol cabin et. Fina lly, set ch annel

0 back to type K thermocouple.

Verifying Channel

Conf igurat ion

Changes

When executing a dynamic channel configuration change, there is

always a del ay from the time the ladder pr ogram makes the chang e to

the time the 1746-NT8 supplies a data word using that new

configuration information. Also, the ladder program should use the

thermocouple temperature data location N10:20 for thermocouple

temperature readings and data location N10:12 for CJC temperature

readings.

Important: During configuration alteration, the state of each

modified channel can not be determined until after one

module update time.

Note: N1 0:2 /1 t hr ough N1 0:2/4 have t he i npu t t ype for typ e K

Thermocouple (0001). N10:8/1 through N10:8/4 have

the input type for CJC Temperature Sensor (1111).

5-4 Programming Examples

Publication 1746-6.22

S:1

COP

Copy File

Source #N10:0

Dest #O:1.0

Length 8

COP

#NT8_CONFIGURATION

B3:6

CHECKING_CJC

B3:6

CHECKING_CJC MOV

Move

Source I:1.0

3744<

Dest N10:20

3744<

MOV

CH0_TEMP

COP

Copy File

Source #I:1.1

Dest #N10:21

Length 7

COP

T11:0

CJC_CYCLE_TMR/DN

TON

Timer On Delay

Timer T11:0

Time Base 1.0

Preset 60<

Accum 20<

TON

CJC_CYCLE_TMR

T11:0

CJC_CYCLE_TMR/DN MOV

Move

Source N10:8

-32737<

Dest O:1.0

-32767<

MOV

NT8_CONFIGURATION

B3:6

CHECKING_CJC

During the first pass, send the channel configuration data to the thermocouple module.

First Pass

If not Checking CJC, copy Channel 0 temperature data into data location for use. Temperature control logic should use

N10:20 rather than the TC input image (I:1.0) to eliminate problems during CJC checking.

Copy temperature data from Channels 1-7 to data registers for use.

Repeating 60 seconds timer (T11:0) which starts the CJC check cycle.

Every 60 seconds, start CJC check cycle by changing Channel 0 configuration word and latching Checking CJC bit (B3/

100).

0000

0003

0004

0002

0001

Programming Examples 5-5

Publication 1746-6.22

Data Table for Configuration Change s

B3:6

CHECKING_CJC

TON

Timer On Delay

Timer T11:1

Time Base 1.0

Preset 7<

Accum 0<

TON

CJC_CFG_TMR

T11:1

CJC_CFG_TMR/DN

OSR

B3:0

MOV

Move

Source I:1.0

3744<

Dest N10:12

329<

MOV

CJC_TEMP

T11:1

CJC_CFG_TMR/DN MOV

Move

Source N10:0

-32767<

Dest O:1.0

-32767<

MOV

NT8_CONFIGURATION

TON

Timer On Delay

Timer T11:2

Time Base 1.0

Preset 7<

Accum 0<

TON

REG_CFG_TMR

T11:2

REG_CFG_TMR/DN

B3:6

CHECKING_CJC

END

Wait 7 seconds for Channel 0 to accept CJC configuration and provide a data value (time depends

on module configuration).

Copy CJC Temperature (I:1.0) into CJC register (N10:12)

Move Channel 0’s regular configuration word into the Channel 0 configuration word and start timer to ensure word has

been accepted prior to taking the thermocouple temperature readings.

When CJC check cycle is completed (T11:2/DN is set), reset the Checking CJC Bit (B3/100).

0005

0009

0008

0007

0006

address 15 data 0 address 15 data 0

N10:0 0000 0010 0010 0011 N10:8 0000 0010 0011 1111

N10:1 0000 0010 0010 0011

N10:2 0000 0010 0010 0011

N10:3 0000 0010 0010 0011

N10:4 0000 0010 0010 0011

N10:5 0000 0010 0010 0011

N10:6 0000 0010 0010 0011

N10:7 0000 0010 0010 0011

5-6 Programming Examples

Publication 1746-6.22

After a chan nel confi guratio n word is chang ed by the ladder logic , the

module may not update the processor’s input image until one update

time later . In order to ensure that the program is using the proper input

data, t he ladde r logic should wa it one update t ime plus one cali bration

time to ensure that the new input data matches the channel

configuration requested. The above table shows how to calculate the

update time and autocalibration time for the channel configuration

being used.

Update Time Calculation

Ch 0 Update Time 0.470

Ch 0 Open Circuit Check 0.045

Ch 1 Update Time 0.470

Ch 1 Open Circuit Check 0.045

Ch 2 Update Time 0.470

Ch 2 Open Circuit Check 0.045

Ch 3 Update Time 0.470

Ch 3 Open Circuit Check 0.045

Ch 4 Update Time 0.470

Ch 4 Open Circuit Check 0.045

Ch 5 Update Time 0.470

Ch 5 Open Circuit Check 0.045

Ch 6 Update Time 0.470

Ch 6 Open Circuit Check 0.045

Ch 7 Update Time 0.470

Ch 7 Open Circuit Check 0.045

CJC Checking 0.290

Update Time 4.410

Autocalibration Time Calculation

Auto-Calibration for 10 Hz 1.975

Auto-Calibration for 60 Hz 0.525

Total Auto-Calibration 2.500

Max Time Between Updates 6.910

Programming Examples 5-7

Publication 1746-6.22

Interfacing to the PID

Instruction The thermocouple module was designed to interface directly to the

SLC 5/02™ or la ter proces sor PID inst ruction withou t the need for an

interm ediate sca le operatio n.

Example - Use 1746-NT8 channel data as the process variable in the

PID i nstruction.

1. Select scaled-for-PID as the data type in the channel

configuration word.

2. Specify the thermocouple channel data word as the process

variable fo r the PID instruction.

In this example, the value -32701 (8043 H) is the numeric equivalent

of configurat ion word N10: 0 for channel 0. I t i s configured fo r a type

K thermocouple, scaled-for-PID, zero the signal for an open-circuit,

10 Hz, °C, and channel enabled.

Programming for PID Control Example

MOV

MOVE

Source N10:0

-32701

Dest O:3.0

s:1

] [

PID

Control Block N11:0

Process Variable I:3.0

Control Variable N11:23

Control Block Length 23

SCL

SCALE

Source N11:23

Rate [/10000]

Offset

Dest

Program Listing

First Pass Bit Initialize NT8

Channel 0

Rung 2:0

Rung 2:2

Rung 2:1

The Rate and Offset parameters should be set per your

application. The Destination will typically be an analog

output channel.

5-8 Programming Examples

Publication 1746-6.22

Monitoring Channel

Status Bits The following example shows how to monitor the open-circuit error

bits of each channel and set an alarm in the processor if one of the

thermocouples opens. An open-circuit error can occur if the

thermocouple breaks, one of the thermocouple wires gets cut or

disconnected from the terminal block, or if the CJC sensors are not

installed or are damaged.

The example shows how to automatically switch between reading the

chann el stat us words a nd chann el senso r data wor ds. Spe cifical ly, this

example shows a simple method of utilizing a timer to periodically

switch between reading the channel status and data words.

The program utilizes a timer a cc um ula tor value to deter mi ne wh en to

set up the configuration words and when to read in the channel status

and channel data information. The channel status information is

copied from the I:2.0 to I:2.7 registers into registers N7:10 to N7:17.

The channel data information is copied from I:2.0 to I:2.7 into

registers N7:0 to N7:7. This allows sensor data and channel status

informat ion to be acces sed at any time from the se registe rs. However ,

when the module channels are configured to read sensor data, the

channel status words (as reflected in N7:10 to N7:17) are not being

dynamically updated, and vice-versa.

Important: If a CJC i nput i s not instal led or i s damaged, al l e nab led

thermocouple alarms are set, and all enabled

thermocouple channel LEDs flash.

Programming Examples 5-9

Publication 1746-6.22

Monitoring Channel Status Bits Example

S:1

COP

Copy File

Source #N10:0

Dest #O:1.0

Length 8

COP

#NT8_CH_CNF

FLL

Fill File

Source 0

Dest #N10:20

Length 8

FLL

#NT8_CH0_STS_FLAGS

CLR

Clear

Dest B3:7

0000000000000001<

CLR

B3:6

NT8_CHECKING_STS COP

Copy File

Source #I:1.0

Dest #N10:30

Length 8

COP

#NT8_LAST_TEMP_READ

T11:0

NT8_STS_CHECK_TMR/DN

TON

Timer On Delay

Timer T11:0

Time Base 1.0

Preset 60<

Accum 10<

TON

NT8_STS_CHECK_TMR

T11:0

NT8_STS_CHECK_TMR/DN

B3:6

NT8_CHECKING_STS

COP

Copy File

Source #N10:10

Dest #O:1.0

Length 8

COP

#NT8_CH_CNF

B3:6

NT8_CHECKING_STS

TON

Timer On Delay

Timer T11:1

Time Base 1.0

Preset 7<

Accum 0<

TON

NT8_STS_CNF_TMR

During 1st program scan, copy thermocouple channel configuration words (N10:0 - N10:7) to NT8. In addition, initialize

channel error registers (N10:20 - N10:27) and Error Flags (B3/112 - B3/119).

If the NT8 is not checking channel status, store the thermocouple readings in the NT8 last channel reading registers

(N10:37). These registers should be used in the remainder of the program (e.g. for temperature control) instead of the

NT8 I/O image location.

T11:0 is a repeating 60-second timer which initiates the NT8 channel status check.

Every 60 seconds, initiate a NT8 channel status check by latching the NT8 channel status checking bit and copying the

“Status check” configuration words (N10:10 - N10:7) to the NT8 configuration words.

After copying the “Status Check configuration words” start a 7-second timer (T11:1) to allow the NT8 to update its I/O

image to the channel status words. The time required for the NT8 to update its I/O image is dependent on the NT8

configuration. Note, the time required be greater than the channel update time including the autocalibration time.

0004

0000

0001

0002

0003

5-10 Programming Examples

Publication 1746-6.22

T11:1

NT8_STS_CNF_TMR/DN

OSR

B3:6

NT8_CHECK_FLAGS MOV

Move

Source 0

Dest B3:7

0000000000000001<

MOV

MVM

Masked Move

Source I:1.0

Mask 0F000h

-4096<

Dest N10:20

4096<

MVM

NT8_CH0_STS_FLAGS

NEQ

Not Equal

Source A N10:20

4096<

Source B 0

NEQ

NT8_CH0_STS_FLAGS

B3:7

NT8_CH0_ERROR

MVM

Masked Move

Source I:1.1

Mask 0F000h

-4096<

Dest N10:21

MVM

NT8_CH1_STS_FLAGS

NEQ

Not Equal

Source A N10:21

Source B 0

NEQ

NT8_CH1_STS_FLAGS

B3:7

NT8_CH1_ERROR

MVM

Masked Move

Source I:1.2

Mask 0F000h

-4096<

Dest N10:22

MVM

NT8_CH2_STS_FLAGS

After waiting for the NT8 to update its I/O image, check each channel’s status error bits by masking off the

appropriate bits and checking if these bits are set (non-zero). If an error is detected, set the appropriate channel

status error bits (B3:112 - B3/119). Rung 5 checks channels 0-3).

0005

Programming Examples 5-11

Publication 1746-6.22

NEQ

Not Equal

Source A N10:22

Source B 0

NEQ

NT8_CH2_STS_FLAGS

B3:7

NT8_CH2_ERROR

MVM

Masked Move

Source I:1.3

Mask 0F000h

-4096<

Dest N10:23

MVM

NT8_CH3_STS_FLAGS

NEQ

Not Equal

Source A N10:23

Source B 0

NEQ

NT8_CH3_STS_FLAGS

B3:7

NT8_CH3_ERROR

T11:1 B3:6

DN 6

NT8_STS_CNF_TMR/DN NT8_CHECK_FLAGS2 MVM

Masked Move

Source I:1.4

Mask 0F000h

-4096<

Dest N10:24

MVM

NT8_CH4_STS_FLAGS

NEQ

Not Equal

Source A N10:24

Source B 0

NEQ

NT8_CH4_STS_FLAGS

B3:7

NT8_CH4_ERROR

MVM

Masked Move

Source I:1.5

Mask 0F000h

-4096<

Dest N10:25

MVM

NT8_CH5_STS_FLAGS

After waiting for the NT8 to update its I/O image, check each channel’s status error bits by masking off the appropriate

bits and checking if these bits are set (non-zero). If an error is detected, set the appropriate channel status error bits

(B3:112 - B3/119). Rung 6 checks channels 4 - 7.

0006 OSR

5-12 Programming Examples

Publication 1746-6.22

NEQ

Not Equal

Source A N10:25

Source B 0

NEQ

NT8_CH5_STS_FLAGS

B3:7

NT8_CH5_ERROR

MVM

Masked Move

Source I:1.6

Mask 0F000h

-4096<

Dest N10:26

MVM

NT8_CH6_STS_FLAGS

NEQ

Not Equal

Source A N10:26

Source B 0

NEQ

NT8_CH6_STS_FLAGS

B3:7

NT8_CH6_ERROR

MVM

Masked Move

Source I:1.7

Mask 0F000h

-4096<

Dest N10:27

MVM

NT8_CH7_STS_FLAGS

NEQ

Not Equal

Source A N10:27

Source B 0

NEQ

NT8_CH7_STS_FLAGS

B3:7

NT8_CH7_ERROR

T11:1

NT8_STS_CNF_TMR/DN COP

Copy File

Source #N10:0

Dest #O:1.0

Length 8

COP

#NT8_CH_CNF

After updating the error status registers and flags, copy the “regular” NT8 channel configuration words into the NT8 I/O

image. Begin 7-second timer to wait for the NT8 to change its I/O image back to the regular channel configuration.

Again, the time required by the NT8 to change its I/O image is dependent on the NT8 configuration.

0007

Programming Examples 5-13

Publication 1746-6.22

PLC 5 Example with

NT8 in Remote I/O

Rack

The foll owing exa mple s hows sample l adder l ogic when using a P LC/

5 control le r t o cont rol the modul e in remot e ra ck a cross the Remot e I /

O network. The PLC/5 must use Block transfer reads and writes to

communicate with the 1746-NT8 module in a remote rack. Note, the

example prov ides code which will re config ure the modul e if the PLC/

5 senses are remote rack fault. Also, the PLC/5 processor uses the

exact same configuration words as the SLC 500 processors.

TON

Timer On Delay

Timer T11:2

Time Base 1.0

Preset 7<

Accum 0<

TON

NT8_REG_CNF_TMR

T11:2

NT8_REG_CNF_TMR/DN

B3:6

NT8_CHECKING_STS

END

After the NT8 has restored its normal I/O image, clear the NT8 checking status bit (B3/100).

0008

0009

5-14 Programming Examples

Publication 1746-6.22

S:1

step

B3:0

NT8_CONFIGURED

B3:0

NT8_CONFIGURED MVM

Masked Move

Source N30:2

256<

Mask 0FH

15<

Dest N11:3

MVM

RIO_RACK1_FLT

NEQ

Not Equal

Source A N11:3

Source B 0

NEQ

RIO_RACK1_FLT

B3:0

NT8_CONFIGURED

B3:0

NT8_CONFIGURED BT20:1

NT8_BTW/EN

BTW

Block Transfer Write

Module Type Generic Block Transfer

Rack 001

Group 0

Module 0

Control Block BT20:1

Data File N12:10

Length 8

Continuous No

BTW

NT8_BTW

BT20:1

BTW_DONE

B3:0

NT8_CONFIGURED

B3:0

NT8_CONFIGURED BT20:0

BTR_TRIGGER

BTR

Block Transfer Read

Module Type Generic Block Transfer

Rack 001

Group 0

Module 0

Control Block BT20:0

Data File N12:0

Length 8

Continuous No

BTR

END

During the first scan, clear the NT8 Configurated bit (B3/4) to initiate the NT8 configuration process.

First scan

or SFC

If the NT8 is configured and a rack fault occurs, clear the NT8 Configured bit (B3/4) to initiate the NT8

configuration proces s.

Until the NT8 is configured, send the 8 configuration words (N12:10-17) to the NT8 using repeating BTW’s.

When the NT8 is configured latch the NT8 Configured bit (B3/4).

If the NT8 is configured, read the 8 input words into N12:0 - N12:7 using repeating BTR’s.

Publication 1746-6.22

Chapter

Tr oublesho oting Yo ur Module

This chapter describes troubleshooting with channel-status and

module-status LEDs. It explains the types of conditions that might

cause the module to flag an error and suggests what corrective action

you could take. Topics include:

• module and chan nel diagnost ics

• LED indicators

• Interpreting I/O error codes

• troubleshooting flowchart

Module and Channel

Diagnostics The module operates at two levels:

• module le vel

• chann el lev el

Module-level operation includes functions such as powerup,

configuration, and communication with the SLC processor. Channel-

level operation includes functions such as data conversion and open-

circuit detection. The module performs internal diagnostics at both

levels an d imme diate ly in dic ates detec ted er ror cond ition s wi th ei ther

of its status LEDs. See the LED troubleshooting tables on page 6-2

for LED operati on.

Module Diagnostics at Powerup

At module powerup, the module performs a series of internal

diagnostic tests. If the module detects a failure, the module status

LED remains off.

Channel Diagnostics

When a channel is enabled, the module checks for a valid

configuration. Then on each scan of its inputs, the module checks for

out-of-range and open-circuit fault conditions of its inputs including

the CJC input.

When the module detects a failure of any channel diagnostic test, it

causes the channel status LED to blink and sets the corresponding

chann el fault bit (bits 12-15 o f the channel s tatus word). Cha nnel fault

bits and LEDs are self-clearing when fault conditions are corrected.

6-2 Troubleshooting Your Module

Publication 1746-6.22

LED Indi cators The module has nine LEDs; as shown below.

• eight channel-status LEDs, numbered to correspond with each

channel

• one module-status LED

LED Troubleshootin g Tables

Module-status LED

Module-status and Channel-status LED

Important: If you clear the channel enable bit, the channel status

bits are reset.

INPUT

LEDs for Channels 0-7

LED for Module Status Channel

Status

Module

Thermocouple/mV

If Module

Status LED

is: Then: Take this Corrective Action:

On The module is

operating properly. No action required.

Off The module is turned

off, or it detected a

module fault. Cycle power. If the condition persists, call your

local Allen-Bradley distributor for assistance.

Flashing Jumper may in wrong

position Check jumper 1position.

If Module

Status

LED is: And Channel

Status LED is: Then: Take this Corrective Action:

On The channel is

enabled No action required.

Flashing

The module

detected: open-

circuit condition,

under-range

condition, over-

range condition

Examine error bits in status word

If bit 12=1, the input has an open

circuit

If bit 13=1, the input value is under

range

If bit 14=1, the input value is over

range

If bit 15=1, the channel has a

diagnostic channel error

Off The module is in

power up, or the

channel is

disabled. No action is required.

Troubleshooting Your Module 6-3

Publication 1746-6.22

Channel-status LEDs (Green)

The channel -statu s LED operates wit h status bi ts in the channel st atus

word to indicate the following faults detected by the module:

• invalid channel configuration

• an open-circuit input

• out-of-range errors

• selected filter frequency data acquisition or auto-calibration

errors

When the module detects any of the following fault conditions, it

causes the channel-status LED to flash and sets the corresponding

fault bi t in the channel sta tus word. Channel faul t bits (bits 12 thr ough

15) and channel-status LEDs are self-clearing when fault conditions

are corrected.

Open-circuit Detection (Bit 12)

If open-circuit detection is enabled for an input channel, the module

tests the channel for an open-circuit condition each time it scans its

input. Open -circui t de te ct ion is a lway s performed for the CJC inputs.

Possible causes of an open circuit include:

• broken thermocouple or CJC sensor

• thermocouple or CJC sensor wire cut or disconnected

• millivolt input wire cut or disconnected

Out-of-Range Detection (Bit 13 for Under Range, bit 14 for Over

Range)

The module tests all enabled channels for an out-of-range condition

each time it scans its inputs. Possible causes of an out-of-range

condition include:

• the tempe ratur e is too hot or t oo cold for t he the rmocoupl e bein g

used

• a type B thermocouple may be registering a °F value in

Engineering Units x1 beyond the range allowed by the SLC

processor (beyond 32,767) for the data word

• a CJC senso r may be damage d or the t emperat ure be ing de tecte d

by the CJC may be outside the CJC sensor range limits

6-4 Troubleshooting Your Module

Publication 1746-6.22

Channel Error (Bit 15)

The module sets this fault bit when it detects any of the following:

Configur ati on err or s:

• configuration bits 1 through 4: invalid input type = 1010, 1011,

1100, 1101, or 1110

• configuration bits 12 through 14: invalid non-zero bit setting

• invalid data acquisition of an input channel

• the filter freq uency selected f or the valid channel currentl y fails

auto -ca li bration ran ge checks

Module Status LED (Green)

The module-status LED indicates when the module detects a

nonre covera ble fa ult at power up or duri ng opera tion. For th is type of

fault, the module:

• no longer communicates with the SLC processor

• disables all channels

• clears all data and status words

A module failure is non-recoverable and requires the assistance of

your local Allen-Bradley distributor.

Interpre tin g I/O Error

Codes I/O error codes appear in word S:6 of the SLC processor status file.

The first two digits of the error code identify the slot (in hexadecimal)

with the error. The last two digits identify the I/O error code (in

hexadecimal).

The error codes that apply to your module include (in hexadecimal):

• 50 through 5E

• 71 (watchdog error)

• 90 through 94

For a description of the error codes, refer to the SLC 500 Instruction

Set Reference Manual, publication 1746-6.15.

Troubleshooting Your Module 6-5

Publication 1746-6.22

Troubleshooting Flowchart

Check LEDs

on module.

Module Status

LED(s) off. Mo du le S t at u s

LED(s) on. Channel

Status LED(s)

flashing.

Channel

Status LED(s)

off.

Channel

Status LED(s)

on.

Module fault

condition. Normal

module

operation. Fault

condition.

Channel is not

enabled. Channel is

enabled and

working.

Check to see that

module is seated

properly in

chassis. Cyc le

power.

End. Are

faulted channel(s)

configured for mV

or thermocouple

input?

mV Enable channel if

desired by setting

channel config.

word (bit 0=1) .

Retry.

End.

Is more than

one LED

blinking?

Yes

CJC fault has

probably

occurred

Check channel

status word bits

12 through 15.

Bit 15

set (1)

Bit 12

set (1)

Bit 14

set (1)

Bit 13

set (1)

Channel error. Check

configuration word bits 1

through 4 for val id input

type configu ration and

ensure bits 12 through 14

are set to zero. Retry.

Over-range condition exists.

The input signal is greater

than the high scale limit for

the channel or the CJC

connections. Correct and

retry.

Check that wiring is secure

at both CJCs and that the

temperat ure within the

enclosure is in the range

limits of the CJC sensor.

Is problem

corrected?

Yes

Under-range condition

exists. The input signal is

less than the low scale limit

for the channel or the CJC

connections. Correct and

retry.

An open-circuit condition

is present. Check channel

and CJC wiring for open or

loose connections. Retry.

Is problem

corrected?

Yes

End.

Is problem

corrected? Yes

Contact your local

Allen-Bradley

distributor

Contact your local

Allen-Bradley

distributor.

Contact your local

Allen-Bradley

distributor.

Thermocouple

Publication 1746-6.22

Chapter

Maintaining Your Module And

Safety Consideration s

Read this chapter to familiarize yourself with:

• preventive maintenance

• safety considerations

The National Fire Protection Association (NFPA) recommends

maintena nce pro cedures f or elect rical e quipment. Refer t o articl e 70B

of the NFPA for general safety -related wor k practices.

Preventive

Maintenance The printed circuit boards of your module must be protected from

dirt, oil, moisture, and other airborne contaminants. To protect these

boards, install the SLC 500 system in an enclosure suitable for its

operating environment. Keep the interior of the enclosure clean, and

whenever possible, keep the enclosure door closed.

Also , regul arly inspect the ter m inal connect ions fo r tightness. Loose

connections may cause a malfunctioning of the SLC system or

damage to the components.

Safety Considerations Safety is always the most important consideration. Actively think

about the safety of yourself and others, as well as the condition of

your equipment. The following are some things to consider:

Indicator Lights – When the module status LED on your module is

illuminated, your module is receiving power.

Activating Devices When Troubleshooting – Never reach into a

machine to activate a device; the machine may move unexpectedly.

Use a wooden stick.

ATTENTION: Possible Loose Connections

Before inspecting connections, always ensure that

incoming power is OFF.

Failure to observe this precaution can cause personal

injury and e quipment damage.

7-2 Maintaining Your Module And Safety Considerations

Publication 1746-6.22

Standing Clear Of Machinery – When troubleshooting a problem

with any SLC 500 system, have all personnel remain clear of

machinery. The problem may be intermittent, and the machine may

move unexpectedly. Have someone ready to operate an emergency

stop switch.

Safety Circuit s – Circuits installed on machinery for safety reasons

(like over-travel limit switches, stop push-buttons, and interlocks)

should always be hard-wired to the master control relay. These

circuits should also be wired in series so that when any one circuit

opens, the master control relay is de-energized, thereby removing

power. Never modify these circuits to defeat their function. Serious

injury or equipment damage may result.

Refer to your system’s Installation & Operation Manual for more

information.

ATTENTION: Possible Equipment Operation

Never reach into a machine to actuate a switch. Also,

remove all electrical power at the main power

disconnect switches before checking electrical

connections or inputs/outputs causing machine motion.

Fail ur e t o observe t hese prec aut ions can cause per sonal

injury or equipment damage.

ATTENTION: Explosion Hazard

• Sub stitution of c omponents may impai r suitability

for Class 1 Division 2.

• Do not disconnect equipment unless power has

been switched off or the area is known to be non-

hazardous.

• When in hazardous locations, turn off power

before replacing or wiring modules.

Note: T his equipmen t is suit able fo r use in Cla ss 1, Divisi on 2,

groups A, B, C, and D or non-hazardous locations only.

Publication 1746-6.22

Appendix

Module Specificat ion s

This appendix lists the specifications for the 1746-NT8

Thermocouple/millivolt Input Module.

Electrical

Specifications

Physical

Specifications

Backplane Current Consumption 120 mA at 5V dc

70 mA at 24Vdc

Backplane Power Consumption 2.28W maximum (0.6W at 5V dc, 1.68W at 24V

dc)

Number of Channels 8 (backplane and channel-to-channel isolated)

I/O Chassis Location Any I/O module slot except 0

A/D Conversion Method Sigma-Delta Modulation

Input Filtering Low pass digital filter with programmable notch

(filter) frequencies

Normal Mode Rejection (between [+] input

and [-] input) Greater than 100 dB at 50/60 Hz

Common Mode Rejection (between input

and ground) Greater than 100 dB at 50/60 Hz

Input Filter Cut-Off Frequencies

2.6 Hz at 10 Hz filter frequency

13.1 Hz at 50 Hz filter frequency

15.72 Hz at 60 Hz filter frequency

65.5 Hz at 250 Hz filter frequency

Greater than 100 dB at 50/60 Hz

Calibration Module autocalibrates at power-up and

approximately every two minutes afterward

Input Over-voltage Protection ±30V dc continuous 600W pulsed for 1 msec.

Isolation 500V dc continuous between inputs and chassis

ground and between inputs and backplane.

12.5V dc continuous between channels.

LED Indicators 9 green status indicators, one for each of 8

channels and one for module status

Module ID Code 3533

Recommended Cable:

for thermocouple inputs…

for mV inputs…

Appropriate shielded twisted pair

thermocouple extension wire1

Belden™ 8761 or equivalent

Maximum Wire Size One 14 AWG wire or two 22 AWG wires per

terminal

1. Refer to the thermocouple manufacturer for the correct extention wire.

A-2 Module Specifications

Publication 1746-6.22

Environmental

Specifications

Inpu t S p ecifications

Overall Accuracy

The accuracy of the module is determined by many aspects of the

hardware and software functionality of the module. The following

discussion explains what the user can expect in terms of accuracy

based on the thermocouple and millivolt inputs for the 1746-NT8

module.

Oper ating Temperature 0°C to +60°C (+32°F to +140°F )

Storage Temperature -40°C to +85°C (-40°F to +185°F)

Relative Humidity 5% to 95% (without condensation)

Certification UL & CU L approved

Hazardous Environment Classification Class I Division 2 Hazardous E nviro nment

Groups A, B, C, D

EMC CE compliant

Type of Input (Selectable

Thermocouple Type J -210°C to +760 C (-346°F to +1400°F)

Thermocouple Type K -270°C to +1370°C (-454°F to +2498°F )

Thermocouple Type T -270°C to +400°C (-454°F to +752°F)

Thermocouple Type E -270°C to +1000°C (-454°F to +1832°F )

Thermocouple Type R 0°C to +1768°C (+32°F to +3214°F)

Thermocouple Type S 0°C to +1768°C (+32°F to +3214°F)

Thermocouple Type B +300°C to +1820°C (+572°F to +3308°F)

Thermocouple Type N 0°C to +1300°C (+32°F to +2372°F)

Millivolt (-50mV dc to +50mV dc)

Millivolt (-1 00mV dc to +100mV dc)

Thermocouple Linearization NIST ITS-90 standard

Cold Junction Compensation Accuracy ±1.72°C, -25°C to +105°C

Input Impedence Greater than 10M

Temperature Scale (Selectable) °C or °F and 0.1°C or 0.1°F

DC Millivolt Scale (Selectable) 0.1 mV or 0.01 mV

Open Circuit Detection

(Selectable) Upscale, Downscale, Zero, or Disabled

Time to Detect Open Circuit One channel cycle time

Input Step Respon se 0 to 95% in 400 msec (10 Hz)

Display Resolution See Channel Data Word Resolution table on page 4-8

Overal l Module Accuracy at

25°C (77°F) See Module Accuracy Tables, page A-3

Overall Module Accuracy See Module Accuracy Tables, page A-3

Overall Module Drift See Module Accuracy Tables, page A-3

Modu le Update Time Dependent upon enabled channels (see Update Time, page 3-7

Channel Turn-Off Time Up to one module update time

Module Specifications A-3

Publication 1746-6.22

The accuracies specified as follows include errors due to the cold

juncti on compensat ion for thermocouples an d har dwar e and soft war e

errors associated with the system. The hardware and software errors

include calibration of the system and non-linearity of the ADC. For

the sake of the calculations, the resolution of the ADC was assumed

to be at least 16 bits (use of the 10 Hz, 50 Hz, and 60 Hz filter

frequencies).

Millivolt

For milli volt i nputs , the er ror is ±30 uV typ ical a t 25°C, a nd ±120 uV

maximum over temperature for the 10 Hz, 50 Hz, and 60 Hz filter

frequencies. The 250 Hz filter frequency accuracy is highly

dependent upon operating environment and may be worse in noisy

environments.

As with any high precision analog input device, system grounding

does affect the accuracy of the readings. Care should be taken to

ensure that the proper filter frequency has been selected based on the

environmental conditions in which the module is to be used.

CJC compensation does not affect the millivolt inputs in terms of

accuracy.

The following diagrams are provided to give a measure of “system”

accuracy using tes t data fro m a single test mod ule. The tests recorded

deviation between measured and expected values. This data was

taken over an entire range of the thermocouple (or millivolt range, as

applicable) and over the module’s temperature range (0 - 60°C). The

maximum deviation fo r each thermoco uple temperature (or mi llivolt

range) was plotted.

Note: The 250 Hz frequency should not be applied to

thermocouple inputs (See table on page 3-4).

A-4 Module Specifications

Publication 1746-6.22

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

-100

-99.92

-99.84

-99.76

-99.68

-99.6

-99.52

-50.16

-50.08-50

-49.92

-49.84

-0.18-0.1

-0.02

0.06

0.14

49.8

49.88

49.96

50.04

50.12

50.2

99.56

99.64

99.72

99.8

99.88

99.96

uV Error

uV Err, ±100mV Span, Prop Cts, 60 Hz, 0°C

mV Input

uV Deviation

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

-100

-99.92

-99.84

-99.76

-99.68

-99.6

-99.52

-50.16

-50.08-50

-49.92

-49.84

-0.18-0.1

-0.02

0.06

0.14

49.8

49.88

49.96

50.04

50.12

50.2

99.56

99.64

99.72

99.8

99.88

99.96

uV Error

mV Input

uV Deviation

uV Err, ±100mV Span, Prop Cts, 60 Hz, 25°C

Module Specifications A-5

Publication 1746-6.22

Thermocouple

The following table provides the total error expected of the

thermocouple based on the thermocouple type, and the given

reference point, at 25°C. The calculations assumed typical hardware/

software error and typical CJC accuracy at 25°C.

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

-100

-99.92

-99.84

-99.76

-99.68

-99.6

-99.52

-50.16

-50.08-50

-49.92

-49.84

-0.18

-0.1

-0.02

0.06

0.14

49.8

49.88

49.96

50.04

50.12

50.2

99.56

99.64

99.72

99.8

99.88

99.96

uV Error

uV Err, ±100mV Span, Prop Cts, 60 Hz, 60°C

mV Input

uV Deviation

Thermocouple Type Thermocouple Reference

Point Error

J+275°C (+527°F) ±1.4°C (±2.52°F)

K +550°C (+1022°F) ±1.5°C (±2.7°F)

T +65°C (+149°F) ±1.3°C (±2.34°F)

E +365 °C (+689° F) ±1.0°C (±1.8°F)

R +885°C (+1625°F) ±3.6°C (±6.48°F)

S +885°C (+1625°F) ±3.4°C (±6.12°F)

B +1060°C (+1940° F ) ±2.7 °C (±4.86°F)

N +500°C (+932°F) ±1.3°C (±2.34°F)

A-6 Module Specifications

Publication 1746-6.22

The following table provides the total error expected over the

temperature range of the module (0 to 60°C) for each thermocouple

based upo n t he type, and the given re ference point, at th e extremes of

the temperature range (0 or 60°C). The calculations are based on

maximum hardware/software error and maximum CJC inaccuracy

over temperature.

The diagrams that follow for each thermocouple type give data for a

sample module over the input range of the thermocouple over

temperature. Thermocouples are usually parabolic in their µV to °C

curves. Normally, at the ends of any given thermocouple range, the

ratio of change in temperature increases as a result of a change in

voltage. In other words, at the ends, a smaller change in voltage

result s in a lar ger cha nge in °C. The dat a th at foll ows gives an idea of

a sample module’s error over the thermocouple range, versus at a

single reference point as provided with the tables above.

Thermocou ple Type Thermocouple Reference

Point Error

J+275°C (+527°F) ±3.0°C (±5.4°F)

K +550°C (+1022°F) ±3.0°C (±5.4°F)

T +65°C (+149°F) ±3.4°C (±6.12°F)

E +365°C (+689°F) ±2.5°C (±4.5°F)

R +885°C (+1625°F) ±6.5°C (±11.7°F)

S +885°C (+1625°F) ±7.2°C (±12.96°F)

B +1060°C (+1940°F) ±8.4°C (±15.12°F)

N +500°C (+932°F) ±3.0°C (±5.4°F)

Note: T he dat a was rec ord ed at 60 Hz. Values at 10 Hz and 50

Hz would be comparable.

Module Specifications A-7

Publication 1746-6.22

0.5

1.5

2.5

3.5

4.5

-210

-150

-75

150

195

225

255

285

315

345

375

450

525

600

675

750

Channel Delta

Thermocouple J Deviations Over Temp

Degrees C TC Input

Degrees C Deviation

0.5

1.5

2.5

3.5

4.5

-202

-125

-25

175

300

400

470

510

550

590

630

725

825

925

1025

1125

1225

1325

Channel Delta

Degrees C TC Input

Degrees C Deviation

Thermocouple K Deviations Over Temp

A-8 Module Specifications

Publication 1746-6.22

-252

-225

-175

-125

-75

-40

-20

100

120

140

160

225

275

325

375

Channel Delta

Degrees C TC Input

Degrees C Deviation

Thermocouple T Deviations Over Temp

-252

-200

-125

-50

100

175

250

285

315

345

375

405

435

465

525

600

675

750

825

900

975

Channel Delta

Degrees C TC Input

Degrees C Deviation

Thermocouple E Deviations Over Temp

Module Specifications A-9

Publication 1746-6.22

150

300

450

600

750

805

835

865

895

925

955

985

1100

1250

1400

1550

1700

Channel Delta

Degrees C TC Input

Degrees C Deviation

Thermocouple R Deviations Over Temp

150

300

450

600

750

805

835

865

895

925

955

985

1100

1250

1400

1550

1700

Channel Data

Degrees C TC Input

Degrees C Deviation

Thermocouple S Deviations Over Temp

A-10 Module Specifications

Publication 1746-6.22

594

650

750

850

950

970

990

1010

1030

1050

1070

1090

1110

1130

1150

1200

1300

1400

1500

1600

1700

1800

Channel Delta

Degrees C TC Input

Degrees C Deviation

Thermocouple B Deviations Over Temp

0.5

1.5

2.5

100

200

300

400

420

440

460

480

500

520

540

560

580

600

700

800

900

1000

1100

1200

1300

Channel Delta

Degrees C TC Input

Degrees C Deviation

Thermocouple N Deviations Over Temp

Publication 1746-6.22

Appendix

Using Grounded Junction,

Ungrounded Junction, an d

Exposed Junction Thermocouples

This appendix describes the types of thermocouples available and

explains the trade-offs in using them with the 1746-NT8 module.

Thermocouple

Types There are three (3) types of thermocouple junctions:

• Grounded Junction - The measuring junction is physically

connected to the protective sheath forming a completely sealed

integral junction. If the sheath is metal (or electrically

conductive), then there is electrical continuity between the

junction and sheath. The junction is protected from corrosive or

erosive conditions. The response time approaches that of the

exposed junction type.

• Ungrounded Junction - The measuring junction is electrically

isolated from the protective metal sheath. This may also be

referred to as an insulated junction. This type is often used where

noise would affect the reading and for frequent or rapid

temperature cycling. The response time is longer than the

grounded junction.

• Exposed Junction - The measuring junction does not have a

protective metal sheath, so it is exposed. This junction style

provides the fastest response time but leaves the thermocouple

wires unprotected against corrosive or mechanical damage.

B-2 Using Grounded Junction, Ungrounded Junction, and Exposed Junction Thermocouples

Publication 1746-6.22

The following illustrations show each of the three (3) thermocouple

types.

Grounded Junction

Ungrounded (Insulated) Junction

Exposed Junction

Isolation The 1746-NT8 module provides the following electrical isolation:

• 12.5V dc electrical isolation channel-to-channel

• 500V dc electrical isolation channel-to-chassis ground

• 500V dc electrical isolation channel-to-backplane

Care must be taken when choosing a thermocouple type and

connecting it to the 1746-NT8 module from the environment being

measured. . If adequate precautions are not taken for a given

thermocouple type, the electrical isolation of the 1746-NT8 module

may be compromised.

Measuring Junction is

connected to sheath

Metal Sheath

Extension Wire

Measuring Junction is

isolated from sheath

Measuring Junction

has no sheath

Using Grounded Junction, Ungrounded Junction, and Exposed Junction Thermocouples B-3

Publication 1746-6.22

Grounded Junction Thermocouples

As shown in the following illustration on page B-3, the shield input

terminal s are i nterna lly con nected togethe r, which are then conn ected

to chassis ground. Using grounded junction thermocouples with

electrically conductive sheaths removes the thermocouple signal to

chassis ground isolation of the module. This is inherent to the

thermocou ple co nst ruction. In addit ion, if mul tiple groun ded ju nction

thermocouples are used, the module’s channel-to-channel isolation is

removed sin ce ther e is no isol atio n between si gnal and sheath and the

sheaths are tied together. It should be noted that the isolation is

removed even if the sheaths are connected to chassis ground at a

location other than the module, since the module is connected to

chassis ground.

For grounded junction thermocouples, it is recommended that they

have protective sheaths made of electrically insulated material (e.g.

ceramic), or the me tal prot ective sheaths be floated. The met al

sheaths would need to be floated with respect to any path to chassis

ground or to another thermocouple metal sheath. This means the

metal sheath must be i nsulate d from electrically conductive p rocess

material and have all connections to chassis ground broken. It should

be noted that a floated sheath may result in a less noise immune

thermocouple signal.

1746-NT8

Grounded junction with

nonconductive protective sheath. CH0 MUXES

CH3

Metal sheath with electrical continuity

to thermocouple signal wires.

(floating ground connection)

B-4 Using Grounded Junction, Ungrounded Junction, and Exposed Junction Thermocouples

Publication 1746-6.22

Exposed Junction Thermocouples

Recommended wiri ng for expos ed junction the rmoco upl es is shown

in the following illustration. Us ing exposed ju nction thermoc ouples

may result in removal of channel-to-channel isolation. This may

occur if multiple exposed thermocouples are in direct contact with

electrically conductive process material. To prevent violation of

chann el- to-chann el isolati on:

• For multi ple exposed th ermocouples , do not allow t he measuring

junction of the thermocouple to make direct contact with

electrically conductive process material.

• Use all ungrounded junction thermocouple instead of the

exposed junction type.

1746-NT8

Conductive Material

Exposed junction with

shielded cable

CH 0

CH 3

MUXES

Exposed junction with

shielded cable

Nonconductive Material

Publication 1746-6.22

Glossary

You should understand the following terms and abbreviations before

using this guide.

A/D – Refers to analog-to-digital conversion. The conversion

produces a digital value whose magnitude is proportional to the

instantaneous magnitude of an analog input signal.

Attenuation – The reduction in magnitude of a signal as it passes

through a system. The opposite of gain.

Channel – Refers to one of ei ght, small-sig nal analog input int erfaces

to the modules’s terminal block. Each channel is configured for

connecti on to a th ermoc ouple or DC millivo lt (mV) input device , and

has its own configuration and status words.

Chassis – A hardware assembly that houses devices such as I/O

modules, adapter modules, processor modules, and power supplies.

CJC – (Cold-Junction Compensation) The means by which the

module compensates for the offset voltage error introduced by the

temperature at the junction between the thermocouple lead wire and

the input terminal block (the cold junction).

Common mode rejection ratio (CMRR) – The ratio of a device’s

dif f erential vol tag e gai n to common mode vol tage gain. Expr ess ed in

dB, CMRR is a comparative measure of a device’s ability to reject

interference caused by a voltage common to its terminal relative to

ground.

Common mode voltage – The voltage difference between the

negative terminal and analog common during normal differential

operation.

Configuration word – Contains the channel configuration

information needed by the module to configure and operate each

channel. Informat io n is written to th e conf igurati on wor d thr ough the

logic supplied in your ladder program.

Cut-off frequ ency – The frequency at which the input signal is

attenuated 3 dB by the digital filter. Frequency components of the

input signal that are below the cut-off frequency are passed with

under 3 dB of attenuation for low-pass filters.

dB (decibel) – A logarithmic measure of the ratio of two signal

levels.

Data word – A 16-bit integer that represents the value of the analog

input channel. The channel data word is valid only when the channel

is enabled and there are no channel errors.

G-2 Glossary

Publication 1746-6.22

Digital fil ter – A low-pass filter of the A/D converter. The digital

filter provides high-frequency noise rejection.

Effecti ve reso lut ion – The number of bits in the channel data word

that do not vary due to noise.

Full-scale error (gain error) – The difference in slope between the

actual and ideal analog transfer functions.

Full-scale range (FSR) – The difference between the maximum and

minimum specified analog values.

Gain dr ift – The change in full-scale transition voltage measured

over the operating temperature range of the module.

Input data scaling – Depends on the data format that you select for

the channel data word. You can select from scaled-for-PID or

Engineering Units for millivolt, thermocouple, or CJC inputs, which

you must compute to fit your application’s temperature or voltage

resolution.

Local system – A control system with I/O chassis within several feet

of the processor, and using 1746-C7 or 1746-C9 ribbon cable for

communication.

LSB (least significant bit) – The bit that represents the smallest

value within a string of bits. The “weight” of this value is defined as

the full-scale range divided by the resolution.

Multiplexer – A switching syst em that allows seve ral input signa ls to

share a common A/D converter.

Normal mod e rejection (differential m ode reject ion) – A

logarithmic measure, in dB, of a device’s ability to reject noise

signals between or among circuit signal conductors, but not between

the equipment grounding conductor or signal reference structure and

the signal conductors.

Remote system – A control system where the chassis can be located

several thousand feet from the processor chassis. Chassis

communication is via the 1747-SN Scanner and 1747-ASB Remote

I/O Adapter.

Resolution – The smallest detectable change in a measurement,

typical ly ex presse d in e nginee ring units (e.g. 0 .15° C) or a s number of

bits. For example, a 12-bit value has 4,096 possible counts. It can

therefore be used to measure 1 part in 4096.

Sampling time – The time required by the A/D converter to sample

an input channel.

Glossary G-3

Publication 1746-6.22

Status word – Contains status information about the channel’s

current configuration and operational state. You can use this

info rmatio n in your lad der pro gra m to de term ine whet her th e cha nnel

data word is valid.

Step response time – The time required for the A/D signal to reach

95% of its expected, final value, given a full-scale step change in the

input signal.

Update time – The time for the module to sample and convert a

channel input signal and make the resulting value available to the

SLC processor.

Index I-i

Publication 1746-6.22

Addressing 3-2, 3-4, 3-6, 3-7, 3-9,

4-5, 4-6, 4-9, 4-10, 4-14, 4-15

Allen-Bradley P-3

contacting for assistance P-3

Analog-to-digital conversion G-1

Attenuation G-1

Avoiding electrostatic damage 2-1

Bit channel status 4-14

Bit field

channel filter frequency 4-14

data format 4-5, 4-14

input type 4-5, 4-14

open-circuit 4-9, 4-14

Calibration A-1

Channel

configuration 4-1

configuration word 4-2, 4-4

data word 4-2, 4-8, 4-9, 4-10

diagnostics 6-1

enable bit 4-5

error 4-15, 6-4

filter frequency bit 4-10

filter frequency bit field 4-14

status bit 4-14

update time 4-2

Channel-status LEDs 6-3

Cold junction compensation, CJC

2-10

Common mode rejection G-1

Condition

open-circuit 4-9, 4-10

out-of-range 4-15

over-range 1-4

under-range 1-4

Configuration words G-1

contacting Allen-Bradley for

assistance P-3

Cut-off frequency G-1

Data format bit field 4-5, 4-14

Data resolution 4-9

Data word 4-2, G-1, G-2

Detection

open-circuit 6-3

determining 2-1

determining power requirements 2-

Diagnostic

information 6-4

LEDs 1-3

Drift G-2

Effective resolution G-2

Electrical noise 2-7

Engineering units 4-5, 4-6

to proportional counts 4-7

to scaled-for-PID 4-7

Errorchannel 4-15

full-scale G-2

open-circuit 4-14

over-range 4-10, 4-15

under-range 4-15

Error codes 6-4

I/O 6-1

Exposed junction B-1, B-4

Filter frequency 4-2, 4-10, 4-15

Full-scale

error G-2

range G-2

Gain drift G-2

Gain error G-2

Grounded junction B-1, B-3

Hardware features 1-3

Hot-swapping 2-5

I/O error codes 6-1, 6-4

Indicator lights 7-1

Inputbit field 4-5, 4-14

channel data 4-6

image type bit 4-11

I-ii Index

Publication 1746-6.22

Installing the module 2-1

Junction

exposed B-1, B-4

grounded B-1, B-3

ungrounded B-1

LED indicators 6-1

Low scale value 4-10

LSB G-2

Maintenance 7-1

Millivolt analog input signal ranges

1-1

Module

Addressing 1-4, 3-2

diagnostics 6-1

ID code 3-1

level operation 6-1

status LED 6-4

Normal mode rejection G-2

Open-circuit

bit field 4-9, 4-14

condition 4-9, 4-10

detection 1-4, 6-3

error 4-14

error bits 5-8

Out-of-range

condition 4-15

Over-range

condition 1-4

error 4-10, 4-15

Preventive maintenance 7-1

Programming 3-2, 3-3, 3-4, 3-6, 3-

7, 3-9, 4-5, 4-6, 4-9, 4-10, 4-14, 4-

Proportional counts 4-5, 4-6

Proportional counts to engineering

units 4-7

Range

full-scale G-2

millivolt analog input signal 1-

temperature 1-1

Resolution G-2, G-3

Safety 7-1

circuits 7-2

considerations 7-1

Sampling time G-2

Scaled-for-PID 4-5, 4-6, 5-7

Scaled-for-PID to engineering units

4-7

Shipping 2-6, 2-8, 2-10

Signal attenuation G-1

Static shielded container 2-6, 2-8,

2-10, 3-2, 3-3, 3-4, 3-6, 3-7, 3-9, 4-

5, 4-6, 4-9, 4-10, 4-14, 4-15

Status G-3

Step response time G-3

Temperature

ranges 1-1

units bit 4-10

units field 4-14

Terminal block removal 2-6

Troubleshooting 6-1, 6-2, 6-5

contacting Allen-Bradley P-3

Under-range

condition 1-4

error 4-15

Ungrounded junction B-1

Update time G-2

Useful resolution G-3

Wiring signal cables 2-1

Publication 1746-6.22 - July 1999 xxxxxxx-xx

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