SCM7B34/34N Isolated Linearized 2- Or 3-Wire RTD Input Modules FEATURES DESCRIPTION INTERFACES TO 100 PLATINUM OR 120 NICKEL RTDS Each SCM7B34/34N RTD input module accepts a single channel of 100 Platinum ( = 0.00385) or 120 Nickel ( = 0.00672) RTD input and produces an input voltage in response to a low level current excitation. The input signal is filtered, isolated, amplified, linearized, and converted to a high level analog voltage for output to the process control system (Figure 1). PROVIDES 250A RTD EXCITATION CURRENT LINEARIZES RTD SIGNAL RESPONSE PROVIDES HIGH LEVEL VOLTAGE OUTPUTS These modules incorporate a five-pole filtering approach to maximize both time and frequency response by taking advantage of both Thomson (Bessel) and Butterworth characteristics. One pole of the filter is on the field side of the isolation barrier; four are on the process control system side. 1500Vrms TRANSFORMER ISOLATION ACCURACY, 0.05% TO 0.15% OF SPAN TYPICAL NONCONFORMITY, 0.025% TO 0.07% OF SPAN TYPICAL In response to the low level current excitation signal, the RTD input signal is chopped by a proprietary chopper circuit and transferred across the transformer isolation barrier, suppressing transmission of common mode spikes and surges. The signal is then reconstructed and filtered for process control system output. ANSI/IEEE C37.90.1-1989 TRANSIENT PROTECTION INPUT PROTECTED TO 120Vrms CONTINUOUS NOISE, 500V PEAK (5MHz), 250V RMS (100KHz) Linearization is achieved by creating a non-linear transfer function through the module itself. This non-linear transfer function is configured at the factory and is designed to be equal and opposite to the specific RTD non-linearity. Lead compensation is achieved by matching two current paths thus cancelling the effects of lead resistance. CMRR, UP TO 160dB NMR, UP TO 85dB EASY DIN RAIL MOUNTING CSA CERTIFIED, FM APPROVAL PENDING Modules accept a wide 14 - 35VDC power supply range (+24VDC nominal). Their compact packages (2.13"x1.705"x0.605" max) save space and are ideal for high channel density applications. They are designed for easy DIN rail mounting using any of the "-DIN" backpanels. CE COMPLIANT 1500V Isolation Barrier Shield* + Surge Suppression, Protection, Lead Compensation, LPF 2 (1 pole), and RTD Current Stimulus 1 - RTD X Iso-Chopper IITM Amplifier Pat Pending LPF (4 pole) 4 5 0 VOUT COM Linearization Backpanel Term Block Field-Side NOTE: For 2-wire operation, jumper the (-) and (x) connections on the backpanel term block. +V -V 3 dc Supply * Shield ground-tie shown for ungrounded RTD sensor configuration. Fig 1: SCM7B34/34N Block Diagram DATAFORTH A Burr-Brown Company (R) Process Control System-Side Call 800-444-7644 For Information and Assistance 114 dc Supply/ Oscillator VS (14-35V dc) Module SCM7B34 SCM7B34N 100 Pt RTD (See Ordering Information below) 120 Ni RTD * 120Vrms max ANSI/IEEE C37.90.1-1989 * * 40mW <1 Continuous Short-to-Ground 12V, 14mA * * * * 1500Vrms ANSI/IEEE C37.90.1-1989 160dB * * * (See Ordering Information below) (See Ordering Information below) * * 60ppm/C 1V/C 0.002%(RZ/RSPAN)4/C 0.002% Span/C * * * * 500V 250V 1V 0.02C/ max 250A * * * * * 3Hz 80/85dB 250ms * * * 14 to 35VDC 12mA 0.0001%/%VS * * * 2.13" x 1.705" x 0.605" max 54.1mm x 43.3mm x 15.4mm max * * -40C to +85C -40C to +85C 0 to 90% noncondensing EN50081-1, ISM Group 1, Class A (Radiated, Conducted) EN50082-1, ISM Group 1, Class A (ESD, RF, EFT) * * * * * Input Signal Range Protection Continous Transient Output Signal Range1 Effective Available Power1 Resistance Protection Voltage/Current Limit CMV (Input-to-Output) Continuous Transient CMRR (50 or 60Hz) Accuracy2 Nonconformity3 Stability (-40C to +85C) Gain Input Offset Zero Suppression Output Offset Noise Peak @ 5MHz B/W RMS @ 10Hz to 100kHz B/W Peak @ 0.1Hz to 10Hz B/W Lead Resistance Effect Sensor Excitation Current5 Frequency and Time Response Bandwidth, -3dB NMR (50/60Hz) Step Response, 90% Span Supply Voltage Current1 Sensitivity Mechanical Dimensions(H)(W)(D) Environmental Operating Temperature Range Storage Temperature Range Relative Humidity Emmissions Immunity **RTD STANDARDS TYPE ALPHA COEFFICIENT 100 Pt 120 Ni 0.00385 0.00672 SCM7B SPECIFICATIONS Typical at 25C and +24VDC DIN JIS DIN 43760 JIS C 1604-1989 NOTES *Specification same as preceding model. 1 Output Range and Supply Current specifications are based on minimum output load resistance. Minimum output load resistance is calculated by VOUT2/PE, where PE is the output Effective Available Power that guarantees output range, accuracy, and conformity specifications. 2 Accuracy includes the effects of repeatability, hysteresis, and conformity. 3 Nonconformity is calculated using the best-fit straight line method. 4 RZ is the value of the RTD resistance at the lowest measurement point. RSPAN is the change in resistance over the measurement span. 5 Sensor excitation current is model dependent. ORDERING INFORMATION MODEL ACCURACY2 INPUT RANGE 100 Pt ** SCM7B34-01 -100C to +100C (-148F to +212F) SCM7B34-02 0C to +100C (+32F to +212F) SCM7B34-03 0C to +200C (+32F to +392F) SCM7B34-04 0C to +600C (+32F to +1112F) SCM7B34-05 -50C to +350C (-58F to +662F) 120 Ni ** SCM7B34N-01 0C to +300C (+32F to +572F) SCM7B34N-02 0C to +200C (+32F to +392F) NONCONFORMITY3 TYPICAL MAX TYPICAL MAX 0.075% (0.15C) 0.10% (0.10C) 0.075% (0.15C) 0.05% (0.30C) 0.05% (0.20C) 0.15% (0.30C) 0.2% (0.20C) 0.15% (0.30C) 0.1% (0.60C) 0.1% (0.40C) 0.025% (0.05C) 0.025% (0.025C) 0.025% (0.05C) 0.025% (0.15C) 0.025% (0.1C) 0.05% (0.10C) 0.05% (0.05C) 0.05% (0.10C) 0.05% (0.30C) 0.05% (0.20C) 0.15% (0.45C) 0.3% (0.90C) 0.15% (0.30C) 0.3% (0.60C) 0.06% (0.18C) 0.12% (0.36C) 0.07% (0.14C) 0.14% (0.28C) OUTPUT RANGES AVAILABLE OUTPUT RANGE PART NUMBER MODIFIER +1 to +5V 0 to +5V 0 to +10V (none) A D EXAMPLE SCM7B34-01 SCM7B34-01A SCM7B34-01D 115 Call 800-444-7644 For Information and Assistance DATAFORTH A Burr-Brown Company (R)