Functional Description

3B47-J-03 The 3B47 is a single-channel isolated thermocouple signal-conditioning module which interfaces, amplifies, isolates, protects, linearizes and filters analog input voltages from a J, K, T, E, R, S or B-type thermocouple. The thermocouple input signal is internally linearized to provide an output voltage which is linear with temperature. High accuracy internal cold junction compensation and a predictable upscale open circuit indication provide a complete signal conditioning solution. To accurately measure low level signals in electrically noisy environments, ±1500 V peak of galvanic transformer-based isolation with a common mode rejection (CMR) of 160 dB @ 50/60 Hz and a normal mode rejection (NMR) of 60 dB @ 50/60 Hz are provided. This plug-in, mix-and-match, hot-swappable module is easily field calibrated via front-panel zero and span adjustments.

Inside the 3B47 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). 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.

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.


Figure 1. 3B47 Functional Block Diagram

  3B47 WIP

Figure 2. 3B47 Input Field Connection


Input Types

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

Output Range

0 to +10 V

3B47 Models Available

  Model Input Type Input Range Output Range Accuracy1
Order Now 3B47-J-01 Type J 0°C to +760°C (32°F to +1400°F) 0 V to +10 V 0.76°C
Order Now 3B47-J-02 Type J -100°C to +300°C (-148°F to +572°F) 0 V to +10 V 0.4°C
Order Now 3B47-J-03 Type J 0°C to +500°C (+32°F to +932°F) 0 V to +10 V 0.36°C
Order Now 3B47-K-04 Type K 0°C to +1000°C (+32°F to +1832°F) 0 V to +10 V 1.0°C
Order Now 3B47-K-05 Type K 0°C to +500°C (+32°F to +932°F) 0 V to +10 V 0.38°C
Order Now 3B47-T-06 Type T -100°C to +400°C (-148°F to +752°F) 0 V to +10 V 1.1°C
Order Now 3B47-T-07 Type T 0°C to +200°C (+32°F to +392°F) 0 V to +10 V 0.3°C
Order Now 3B47-E-08 Type E 0°C to +1000°C (+32°F to +1832°F) 0 V to +10 V 1.5°C
Order Now 3B47-R-09 Type R +500°C to +1750°C (+932°F to +3182°F) 0 V to +10 V 1.6°C
Order Now 3B47-S-10 Type S +500°C to +1750°C (+932°F to +3182°F) 0 V to +10 V 1.5°C
Order Now 3B47-B-11 Type B +500°C to +1800°C (+932°F to +3272°F) 0 V to +10 V 3.3°C
  3B47-Custom Type J, K, T, E, R, S, or B * * *

1The CJC sensor accuracy (refer to specification table) should be added to the module accuracy when computing system accuracy.
* Custom Input/Output ranges are available. Refer to configuration guide.

3B47 Specifications
(typical @ +25°C and ±15 V dc, and +24 V dc Power)

Description Model 3B47
Input Ranges
Thermocouple Types J, K, T, E, R, S, B
Standard Ranges Refer to Model Table
Custom Ranges ±5 mV to ±500 mV
Output Range1
Voltage (RL > 2 KΩ) 0 V to +10 V
Initial @ +25°C See Model Table
Stability vs. Temperature
Voltage Output
   Zero ±0.02°C/°C
   Span ±25 ppm of Reading/°C
Zero and Span Adjustment Range3 ±5% of Span
Cold Junction Compensation (CJC)4
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
Input, 0.1 Hz to 10 Hz Bandwidth 0.2 µV rms
Output, 100 kHz Bandwidth 100 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 Voltages
Rated Operation ±(11.5 V dc to 16.5 V dc)
Current +16 mA, -14 mA
Sensitivity ±0.01% span/V
Mechanical Dimensions 3.15" x 3.395" x 0.775"
(80.0 mm x 86.2 mm x 19.7 mm)
Temperature Range
   Rated Performance -25°C to +85°C
   Storage -55°C to +85°C
Relative Humidity 0 to 95% @ +60°C noncondensing
RFI Susceptibility ±0.5% Span error @ 400 MHz, 5 Watt, 3 ft

1 Current output is not available with model 3B47.
2 Includes the combined effects of repeatability, hysteresis, and nonlinearity.
3 A wide range of zero suppression and span adjustment is available to enable field calibration.
4 When used with the CJC temperature sensor provided on the 3B Series backplane. Specifications subject to change without notice.

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