3B37 Isolated, Thermocouple Input
3B37 Isolated, Thermocouple Input

Accurate and System-Ready
Internal cold-junction compensation largely corrects errors arising from parasitic thermocouples formed by thermocouple connection to the input screw terminals, providing an accuracy of ±0.5°C over the +5°C to + 45°C ambient temperature range. The module generates a predictable upscale signal to indicate an open thermocouple; for a downscale response, connect a 47 MΩ, 0.25 Watt resistor across screw terminals 2 and 4 on the 3B Series backplane.
3B Series Custom-Ranging Program
Externally-programmable version Model 3B37-X--00, enable the user to configure a special input range by using the optional plug-on AC1310 ranging card, which houses user-supplied resistors to determine zero and span. To facilitate selecting resistors, a Windows® program, 3B-CUSTOM, calculates resistor values based on the user-desired input/output ranges.
Inside the 3B37 Module
A chopper-stabilized low-drift input amplifier assures stable long-term stability. At the amplifier input, a zero-scale input voltage is subtracted from the input signal to set the zero-scale value. For user convenience, the zero and span optionally can be factory configured to meet custom needs (Model 3B37-CUSTOM) or can be externally programmed (Model 3B37-X-00) via user-supplied resistors inserted in the optional AC1310 plug-on ranging card. Zero suppression can exceed 100% of the input range. This enables suppression of a zero-scale input value many times larger than the total span for precise expanded-scale measurements of a selection portion of an input signal. The differential input circuit on the field side is fully floating, eliminating the need for any input grounding. Signal isolation by transformer coupling uses a proprietary modulation technique for linear, stable and reliable performance A demodulator on the computer side of the signal transformer recovers the original signal, which is then filtered and buffered to provide a low-noise, low-impedance output voltage; this output also drives a voltage-to-current (V/I) converter to provide a simultaneous current output for interfacing versatility.
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Figure 1. 3B37 Functional Block Diagram |
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Figure 2. 3B37 Input Field Connections |
Input Type |
Dual Outputs |
Thermocouples: J, K, T, E, R, S, B |
0 to +10 V or -10 V to +10 V |
0 to 20 mA or 4 to 20 mA |
Model | Input Type | Input Range | Output Ranges1 |
|
Order Now | 3B37-X-00 |
Type J, K, T, E, R, S, or B | Externally Programmable2 |
0 V to +10 V & 0 mA to 20 mA |
Order Now |
3B37-J-01 |
Type J | -100°C to +100°C (-148°F to +1400°F) |
0 V to +10 V & 0 mA to 20 mA |
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3B37-K-02 | Type K |
-100°C to +1350°C (-148°F to +2462°F) |
0 V to +10 V & 0 mA to 20 mA |
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3B37-T-03 |
Type T | -100°C to +400°C (-148°F to +752°F) |
0 V to +10 V & 0 mA to 20 mA |
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3B37-E-04 |
Type E |
0°C to +900°C (+32°F to +1652°F) |
0 V to +10 V & 0 mA to 20 mA |
Order Now |
3B37-R-05 |
Type R |
0°C to +1750°C (+32°F to +3182°F) |
0 V to +10 V & 0 mA to 20 mA |
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3B37-S-05 |
Type S |
0°C to +1750°C (+32°F to +3182°F) |
0 V to +10 V & 0 mA to 20 mA |
Order Now |
3B37-B-06 |
Type B |
0°C to +1800°C (+32°F to +3272°F) |
0 V to +10 V & 0 mA to 20 mA |
3B37-Custom |
Type J, K, T, E, R, S, or B |
* | * |
1 Output current range may be user programmed to 4 mA to 20 mA using jumper supplied.
2 Requires AC1310 ranging card.
* Custom Input/Output ranges are available. Refer to configuration guide.
(typical @ +25°C and ±15 V dc, and +24 V dc Power)
Description | Model 3B37 |
Input Range |
|
Standard Ranges |
Refer to Model Table |
Custom Ranges |
±5 mV to ±500 mV |
Output Range |
|
Voltage (RL > 2K) |
0 V to +10 V; -10 V to +10 V |
Current (RL = 0 to 850Ω)1 |
4 mA to 20 mA or 0 mA to 20 mA |
Maximum Current Output Span |
0 mA to 31 mA |
Accuracy2 | |
Initial @ +25°C |
±0.1% Span + CJC Sensor Error |
Nonlinearity |
±0.01% Span |
Stability vs. Temperature |
|
Voltage Output |
|
Zero | ±0.02°C/°C |
Span | ±25 ppm of Reading/°C |
Current Output4 |
|
Zero | ±25 ppm of Span/°C |
Span | ±25 ppm of Reading/°C |
Zero and Span Adjustment Range4 | ±5% of Span |
Cold Junction Compensation (CJC)5 | |
Initial Accuracy @ +25°C |
±0.5 °C |
Accuracy vs. Temperature, +5°C to +45°C |
±0.5°C (±0.0125°C/°C) |
Input Bias Current | +15 nA |
Input Resistance |
15 MΩ |
Noise |
|
Input, 0.1 Hz to 10 Hz Bandwidth |
0.2 µV rms |
Output, 100 kHz Bandwidth |
50 µV rms |
Bandwidth, -3 dB |
3 Hz |
Output Rise Time, 10% to 90% Span | 200 ms |
Open Input Response |
Upscale |
Open Input Detection Time | 10 seconds |
Common Mode Voltage (CMV) | |
Input-to-Output, Continuous |
±1500 V peak, maximum |
Transient |
ANSI/IEEE C37.90.1-1989 |
Common Mode Rejection (CMR) | |
1 kΩ Source Imbalance, 50/60 Hz | 160 dB |
Normal Mode Rejection, 50/60 Hz | 60 dB |
Input Protection |
|
Continuous |
220 V rms maximum |
Transient | ANSI/IEEE C37.90.1-1989 |
Voltage Output Protection | Continuous Short to Ground |
Current Output Protection |
130 V rms, continuous |
Power Supply Voltages6 |
|
±15 V dc Supplies |
|
Rated Operation | ±(11.5 V dc to 16.5 V dc) |
Current | ±12 mA |
Sensitivity | ±0.01% span/V |
+24 V dc Loop Supply |
|
Rated Operation | +12 V dc to +30 V dc |
Current | +27 mA @ lout = 20 mA |
Sensitivity | ±0.0002% span/V |
Mechanical Dimensions |
3.15" x 3.395" x 0.775" (80.0 mm x 86.2 mm x 19.7 mm) |
Environmental |
|
Temperature Range |
|
Rated Performance | -25°C to +85°C |
Storage | -55°C to +85°C |
Relative Humidity, 24 hours |
0 to 95% @ +60°C noncondensing |
RFI Susceptibility |
±0.5% Span error @ 400 MHz, 5 Watt, 3 ft |
1 For a 0 mA to 20 mA range, a typical minimum output current is 10 µA.
2 Includes the combined effects of repeatability, hysteresis, and nonlinearity.
3 With respect to the voltage output.
4 A wide range of custom zero suppression and span is available with the 3B30-00 and 3B31-00 models, using the AC1310 ranging card.
5 When used with the CJC temperature sensor provided on the 3B Series backplane.
6 +24 V dc loop power is required for driving the current output at loads up to 850Ω. If a current output load of 400Ω or less is applied, +15 V dc is sufficient for loop power. If only voltage output is used, loop power is not required.
Specifications subject to change without notice.