SCM5B37 Thermocouple Input Modules FEATURES The SCM5B modules are designed with a completely isolated computer side circuit which can be floated to ±50V from Power Common, pin 16. This complete isolation means that no connection is required between I/O Common and Power Common for proper operation of the output switch. If desired, the output switch can be turned on continuously by simply connecting pin 22, the Read-Enable pin to I/O Common, pin 19. ● INTERFACES TO TYPES J, K, T, E, R, S, C, N AND B THERMOCOUPLES ● HIGH LEVEL VOLTAGE OUTPUTS ● 1500Vrms TRANSFORMER ISOLATION The SCM5B37 can interface to nine industry standard thermocouple types: J, K, T, E, R, S, C, N, and B. Its corresponding output signal operates over a 0V to +5V range. Each module is cold-junction compensated to correct for parasitic thermocouples formed by the thermocouple wire and screw terminals on the mounting backpanel. Upscale open thermocouple detect is provided by an internal pull-up resistor. Downscale indication can be implemented by installing an external 47MΩ resistor, ±20% tolerance, between screw terminals 1 and 3 on the SCMPB01/02/03/04/05/06 backpanels. ● ANSI/IEEE C37.90.1-1989 TRANSIENT PROTECTION ● INPUT PROTECTED TO 240VAC CONTINUOUS ● 160dB CMR ● 95dB NMR AT 60Hz, 90dB at 50Hz ● ±0.05% ACCURACY ● ±0.02% LINEARITY Signal filtering is accomplished with a six-pole filter which provides 95dB of normal-mode-rejection at 60Hz and 90dB at 50Hz. Two poles of this filter are on the field side of the isolation barrier, and the other four are on the computer side. ● ±1µV/°C DRIFT ● CSA CERTIFIED, FM APPROVED, CE COMPLIANT ● MIX AND MATCH SCM5B TYPES ON BACKPANEL DESCRIPTION Each SCM5B37 thermocouple input module provides a single channel of thermocouple input which is filtered, isolated, amplified, and converted to a high level analog voltage output (Figure 1). This voltage output is logicswitch controlled, allowing these modules to share a common analog bus without the requirement of external multiplexers. After the initial field-side filtering, the input signal is chopped by a proprietary chopper circuit. Isolation is provided by transformer coupling, again using a proprietary technique to suppress transmission of common mode spikes or surges. The module is powered from +5VDC, ±5%. A special input circuit on the SCM5B37 modules provides protection against accidental connection of power-line voltages up to 240VAC. For Class I, Division 2 hazardous location applications, refer to Dataforth installation manual MA1146 (available upon request). +2.5V 100MΩ 4 NC +EXC LPF Isochopper™ Amplifier Pat Pending 4 +In Thermocouple Surge Suppression and Protection 6 3 5 –In 2 LPF 19 +V –V 3 –EXC Precision Reference 1 Backpanel Term Block 20 22 Isolated Computer-Side Power VOUT I/O Common RD EN\ CJC 1 2 Temp Sensor +V –V FIGURE 1. SCM5B37 Block Diagram. DATAFORTH A Burr-Brown Company ® Call 800-444-7644 For Information and Assistance 17 Isolated Field-Side Power Power Oscillator 16 +5V Power Common SPECIFICATIONS Typical at T Module -0.1V to +0.5V -25nA 50MΩ 40kΩ 40kΩ 1500Vrms max ANSI/IEEE C37.90.1-1989 160dB 95dB at 60Hz, 90dB at 50Hz Accuracy(1) Nonlinearity Stability Input Offset Output Offset Gain Noise Input, 0.1 to 10Hz Output, 100kHz Bandwidth, –3dB Response Time, 90% Span Output Range Output Resistance Output Protection Output Selection Time (to ±1mV of VOUT) Output Current Limit ±0.05% Span ±10µV RTI(2) ±0.02% Span ±1µV/°C(3) ±20µV/°C ±25ppm/°C 0.2µVrms 200µVrms 4Hz 0.2s 0V to +5V 50Ω Continuous Short to Ground 6µs at Cload = 0 to 2000pF +8mA Output Enable Control Max Logic “0” Min Logic “1” Max Logic “1” Input Current, “0”, “1” Open Input Response Open Input Detection Time Cold Junction Compensation Accuracy, 25°C Accuracy, +5°C to +45°C Accuracy, –40°C to +85°C Power Supply Voltage Power Supply Current Power Supply Sensitivity Mechanical Dimensions Environmental Operating Temp. Range Storage Temp. Range Relative Humidity RFI Susceptibility TYPE Type J Type K Type T Type E Type R Type S Type B Type C Type N SCM5B 240Vrms max ANSI/IEEE C37.90.1-1989 CMV, Input to Output Continuous Transient CMR (50Hz or 60Hz) NMR MODEL SCM5B37J SCM5B37K SCM5B37T SCM5B37E SCM5B37R SCM5B37S SCM5B37B SCM5B37C SCM5B37N = +25°C and +5V power. SCM5B37 Input Range Input Bias Current Input Resistance Normal Power Off Overload Input Protection Continuous Transient ORDERING INFORMATION A +0.8V +2.4V +36V 0.5µA Upscale 10s ±0.25°C ±0.5°C ±1.25°C +5VDC ±5% 30mA ±2µV/% RTI(2) 2.28" x 2.26" x 0.60" (58mm x 57mm x 15mm) –40°C to +85°C –40°C to +85°C 0 to 95% Noncondensing ±0.5% Span Error at 400MHz, 5W, 3ft INPUT RANGE –100°C to +760°C (–148°F to +1400°F) –100°C to +1350°C (–148°F to +2462°F) –100°C to +400°C (–148°F to +752°F) 0°C to +900°C (+32°F to +1652°F) 0°C to +1750°C (+32°F to +3182°F) 0°C to +1750°C (+32°F to +3182°F) 0°C to +1800°C (+32°F to +3272°F) +350°C to +1300°C (+662°F to +2372°F) –100°C to +1300°C (–148°F to +2372°F) NOTES: (1) Includes nonlinearity, hysteresis and repeatability. Does not include CJC accuracy. (2) RTI = Referenced to input. (3)This is equivalent to °C as follows: Type J 0.020 °C/°C, Types K, T 0.025°C/°C, Type E 0.016°C/°C, Types R, S 0.168°C/°C. Type N 0.037°C/°C, Type C, 0.072°C/°C. OUTPUT RANGE 0V to +5V 0V to +5V 0V to +5V 0V to +5V 0V to +5V 0V to +5V 0V to +5V OV to +5V 0V to +5V Call 800-444-7644 For Information and Assistance DATAFORTH A Burr-Brown Company ®