ET2020/EFA/01/05 - Oxley Developments Co., Ltd.

features

EEPROM non-volatile memory

10 years data retention

Low power, 10 mW typical

Serial and parallel outputs

Micro processor compatible

Non-volatile text storage and recall

Military specifications

description

The 18 pin ceramic dual-in-line elapsed

time indicator (ETI) is assembled using

hybrid technology, ensuring suitability for

applications where severe environmental

conditions maybe encountered.

product information

Elapsed time indicator

ET2020/EFA/01/05

application diagrams

Typical serial and parallel application

diagrams are shown below. The internal

timer is activated whenever the 5V

power supply is applied. No additional

timing control circuitry is required.

The total elapsed time is accumulated in

the internal non-volatile memory for

interrogation through the serial or parallel

interfaces.

parallel mode serial mode

Test pin (8) is for factory purposes

and should be left unconnected

pin assignmentdimensions

VAUX

interrogation

ETIs can be interrogated via serial or

parallel format. The output select (OS)

input is used for selection of

interrogation mode.

serial elapsed time

Bytes 1 and 12 are ASCII carriage return

characters. Bytes 2 to 9 represent the

elapsed time reading and are ASCII

characters. Byte 2 is the most significant

digit. Byte 7 is always “.” and byte 11

“H” denoting units of hours. Elapsed

time measurement is suspended for

typically 300 ms during serial data

output.

serial data

(output select = 0)

Serial data transfer uses two pins, Rx

(receive data) and Tx(transmit data).

Together with a signal common, these

lines constitute a 3 wire serial

communication interface utilising a

standard non-return to zero (NRZ), data

format. Direct interface can be made

with integrated circuit UART devices.

The signals can also be level shifted to

conform to RS232 requirements.

The Rxand Txsignals must meet the

following requirements:

A High level indicates logic 1 (5V) and a

low level indicates logic 0 (0V)

The Rxinput must be a high state prior

to reception of data

A start bit, (logic 0), is

transmitted/received indicating the start

of a message

Bytes of data are transmitted/received

least significant bit first

A stop bit, (logic 1), in the 10th bit

position indicates transmission/reception

of a byte is complete

Baud rate: 9600b/s

Data bits: 8

Start bits: 1

Stop bits: 1

Parity: none

To initiate transmission of serial elapsed

time/pulse count data a unique two

character ASCII command “ET” must be

received at the Rxinput. Following

reception of a valid “ET” command the

ETI will output the elapsed time

message on the Txoutput. If an invalid

command is received an ASCII carriage

return character, (0D hex), is transmitted.

No further serial data received for a

period of 5ms.

product information

characteristics

Operating temperature range -55 to 125ºC

Storage temperature range -55 to 125ºC

Supply voltage VCC 4.5 to 5.5 Vdc

Supply voltage VAUX 4.0 to 5.5 Vdc

Supply current 1mA typical, 2mA max

Timing resolution 0.01 hours

Timing accuracy ±0.1%

Capacity (parallel mode) 104hours/106pulses

Capacity (serial mode) 105hours/107pulses

Pulse count frequency 30 Hz max

Pulse width 10ms min

VOH output logic 1 VCC -1 to VCC

VOLoutput logic 0 VSSto 0.2 x VCC

VIH input logic 1 0.8 x VCCto VCC

VILinput logic 0 VSSto 0.2 x VCC

IZhigh Z leakage current ± 10µA

byte 12345678910 11 12

character cr 00000.00 Hcr

hex 0D 30 30 30 30 30 2E 30 30 20 48 0D

“T”

max

output.

parameter description min max units

tIinitialisation time 600 ms

tRT request time pulse width for

time information only 6 12 ms

tRTT request time pulse width for

time and text information 16 ms

tSDV time to set up first data valid 6 ms

tDV data valid pulse width 90 110 µs

tPDV period of data valid 4.99 5.01 ms

tOT total bus active time 264 ms

tOET total bus active time,

elapsed time only output 15 ms

tZDV time from end of Z state

to first DV 175 typical µs

tDS data set up time 90 typical µs

tRTP request time repetition period 300 ms

product information

BCD parallel output

During DV(1) the digits represent HOURS x 103and HOURS x 102

During DV(2) the digits represent HOURS x 101and HOURS x 100

Serial Text Output

power supply

A single 5 volt power supply, Vccis

required for operation. A separate power

supply input VAUX is also provided for

energisation from a second power

source. A blocking diode is internally

connected to prevent current from VAUX

powering parent equipment connected

to Vcc. This provides cold read facilities

during failure of parent equipment or

when it is powered down.

parallel data

(output select = 1)

Parallel elapsed time/pulse count

interrogation is initiated by holding the

request time input at logic 0 for time

tRT or until the positive edge of DV(1).

The elapsed time/pulse count then

appears sequentially in 3 bytes on

outputs D0-D7. Data is synchronised

with pulses which appear on the data

valid (DV) output. Each byte represents

a 2 digit BCD number. Outputs D7-D4

represent the most significant digit,

outputs D3-D0 represent the least

significant digit. D0 - D7 are tri state

outputs suitable for direct connection

onto a high impedance data bus.

ID(mA)

Vcc - VOH (volts)

product information

Oxley Developments

Company Ltd

Priory Park

Ulverston

Cumbria

LA12 9QG

United Kingdom

t: +44 (0) 1229 483226

f: +44 (0) 1229 580687

e: sales@oxley.co.uk

Oxley Inc

31 Business Park Drive

Branford

CT 06405

USA

t: +1 (203) 488-1033

f: +1 (203) 481-6971

e: sales@oxleyinc.com

Oxley Group

Australia Pty Ltd

PO Box 24

Artarmon

NSW 1570

Australia

t: +61 (0) 2 9460 9112

f: +61 (0) 2 9460 9114

e: sales@oxleyaustralia.com

w: www.oxleygroup.com

ODC:SM:40681/2/08

HOURS x 10-1 and HOURS x 10-2

user programmable text

50 bytes of EEPROM are provided for

user entry and storage of 50 characters

of text information.

The text may record, for example

maintenance and warranty status of

parent equipment. Text may be rewritten

as often as required and can be read by

both serial and parallel outputs. Text can

only be entered serially.

serial text input

serial text interrogation

Serial text interrogation is achieved by

using the ASCII “OX” command.

ordering information

Elapsed time indicator ET2020/EFA/01/05

Non volatile pulse counter PC2020/EFA/01/05

qualification

Originally approved to DEF-STAN 59-61

(`Part 90/257)

Company approvals:

BS EN 9001:2000 (FM 01759)

BS EN ISO 14001:2004 (EMS 60559)

AS EN 9100 REV B

text entry

Text entry can only be made whilst in

serial mode and is initiated by detection

of the ASCII “IX”: command at the Rx

input. Up to 50 ASCII text characters

should then be input, terminated either

by a carriage return or by entry of the

50th character. Text entered will

overwrite previously stored text.

parallel text

interrogation

Parallel text interrogation is initiated by

holding the request time input at

logic 0 for the time tRTT or until the

positive edge of DV(4). Following the 3

bytes of elapsed time/pulse count

information, the ASCII text appears on

outputs D0-D7 synchronised with data

valid pulses DV(4) to DV(53). To

request elapsed time information only,

the request time pulse width should

not exceed tRT max. Elapsed time

measurement is suspended for

typically 300ms during parallel data

4 ms max

0.5 ms min

1.0 ms max