Functional Description

5B37-J-01 The 5B37 is a single-channel signal conditioning module that interfaces, amplifies and filters J, K, T, E, R, S, B, N, and C-type thermocouple and provides an isolated and protected precision output of 0 to +5 V.

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 ±0.25°C @ +25°C ambient temperature. The module generates a predictable upscale signal to indicate an open thermocouple; for a downscale response, connect a 47 MΩ, 0.25 W resistor across screw terminals 1 and 3.

The 5B37 protects the computer side from damage due to field-side overvoltage faults. All models withstand 240 V rms at their input terminals without damage, thereby shielding computer-side circuitry from field-side overvoltage conditions. Further, the 5B37 is mix-and-match and hot-swappable with other 5B Series modules, so can be inserted or removed from any socket in the same backplane without disrupting system power.

Inside the 5B37 Module
A chopper-stabilized input amplifier provides low drift and stable gain. At the amplifier input, a stable, laser-trimmed zero-scale input voltage is subtracted from the input signal to set the zero-scale value. For user convenience, the zero can be optionally factory-set to meet custom needs. This allows suppression of a zero-scale input value many times larger than the total span for precise expanded-scale measurements.

Internal multi-pole lowpass filtering with a four-Hz cutoff (-3 dB) provides 60 dB of normal-mode rejection (noise on signal) and enhancement of common-mode rejection (noise on signal return) at 60 Hz, enabling accurate measurement of small signals in high electrical noise.

Signal isolation by transformer coupling uses a proprietary modulation technique for linear, stable and reliable performance. The differential input circuit on the field side is fully floating, eliminating the need for any input grounding. 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 signal. The output common must be kept within 3 V of power common.

Convenience Features
A series output switch eliminates the need for external multiplexing in many applications. The switch is turned on by an active-low enable input. The enable input should be grounded to power common if the output need not be switched, as on the 5B01 and 5B08 backplanes.

5B37 FBD

Figure 1. 5B37 Functional Block Diagram


Input Types

Thermocouple Types :
J, K, T, E, R, S, B, N, C

Output Range

0 to +5 V
(-5 V to +5 V - custom)

5B37 IFC
Figure 2. 5B37 Input Field Connections

5B37 Models Available
  Model Input Type Input Range Output Range
Order Now5B37-J-01Type J-100°C to +760°C (-148°F to +1400°F)0 V to +5 V
Order Now5B37-K-02Type K-100°C to +1350°C (-148°F to +2462°F)0 V to +5 V
Order Now5B37-T-03Type T-100°C to +400°C (-148°F to +752°F)0 V to +5 V
Order Now5B37-E-04Type E0°C to +900°C (+32°F to +1652°F)0 V to +5 V
Order Now5B37-R-05Type R0°C to +1750°C (+32°F to +3182°F)0 V to +5 V
Order Now5B37-S-05Type S0°C to +1750°C (+32°F to +3182°F)0 V to +5 V
Order Now5B37-B-06Type B0°C to +1800°C (+32°F to +3272°F)0 V to +5 V
Order Now5B37-N-08Type N0°C to +1300°C (+32°F to +2372°F)0 V to +5 V
 5B37-CustomType J, K, T, E, R, S, B, N, C**
* Custom Input/Output ranges are available. Refer to configuration guide.

5B37 Specifications
(typical @ +25°C and Vs = +5 V dc)
Description Model 5B37
Input Ranges
Standard Ranges Refer to Model Table
Custom Ranges±5 mV to ±500 mV
Output Range (RL > 50 kΩ)4-5 V to +5 V or 0 to +5 V
Initial @ +25°C±0.05% Span ±10 µV RTI ±0.05% of Vz1 +CJC Sensor Error
Nonlinearity±0.02% Span
Input Offset vs. Temperature±1 µV/°C
Output Offset vs. Temperature±20 µV/°C
Gain vs. Temperature±0.0025% of Reading/°C
Cold Junction Compensation
Initial Accuracy @ +25°C3±0.25°C (±0.75°C, maximum)
Accuracy, +5°C to +45°C±0.5°C (±0.0125°C/°C)
Input Bias Current-25 nA
Input Resistance
Power On5 MΩ
Power Off40 kΩ
Overload40 kΩ
Input, 0.1 Hz to 10 Hz Bandwidth0.2 µV rms
Output, 100 kHz Bandwidth200 µV rms
Bandwidth, -3 dB4 Hz
Output Rise Time, 10% to 90% Span200 ms
Common-Mode Voltage (CMV)4
Input-to-Output, Continuous1500 V rms, maximum
Output-to-Power, Continuous±3 V, maximum
TransientANSI/IEEE C37.90.1-1989
Common Mode Rejection (CMR)
1 kΩ Source Imbalance, 50/60 Hz160 dB
Normal Mode Rejection (NMR), 50/60 Hz60 dB
Input Protection
Continuous240 V rms, maximum
TransientANSI/IEEE C37.90.1-1989
Output Resistance50 &3937;
Voltage Output ProtectionContinuous Short to Ground
Output Selection Time6 µs @ Cload = 0 to 2,000 pF
Output Enable Control
Max Logic "0"+1 V
Min Logic "1"+2.5 V
Max Logic "1"+36 V
Input Current "0"0.4 mA
Open Input ResponseUpscale
Open Input Response Time10 seconds
Power Supply Voltage+5 V ±5%
Power Supply Current30 mA
Power Supply Sensitivity, RTI±2 µV/% of Vs
Mechanical Dimensions2.275" x 2.375" x 0.595"
(57.8 mm x 59.1 mm x 15.1 mm)
Temperature Range
   Rated Performance-25°C to +85°C
   Operating-40°C to +85°C
   Storage-40°C to +85°C
Relative Humidity0 to 93% @ +40°C noncondensing
RFI Susceptibility±0.5% Span error @ 400 MHz, 5 Watt, 3 ft

1Vz is the nominal input voltage that results in a 0 V output.
2Includes the combined effects of repeatability, hysteresis, and nonlinearity and assumes RL > 50 kΩ. Loads heavier than 50 kΩ will degrade nonlinearity and gain temperature coefficient.
3When used with the model AC1361 CJC sensor (see Accessories section), which is provided on each channel of 5B Series backplanes and mounting cards.
4The output common must be kept within ±3 V of power common.
Specifications subject to change without notice.

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