4WPB100 100-Ohm, Four-Wire PRT Bridge Terminal Input Module


The 4WPB100 provides completion resistors to enable your Campbell Scientific data logger to measure 100-ohm platinum resistive thermometer s(PRT) using the half-bridge four-wire measurement method.

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Benefits and Features

  • Provides high-accuracy completion resistor and convenient wiring for four-wire, 100-ohm PRT measurements
  • Easy to install or remove
  • Connects directly into data logger input terminals
  • Compatible with most Campbell Scientific data loggers


Detailed Description

4-Wire PRT Bridge Module Schematic
(Rf=100 Ω for the 4WPB100)

4WPB100-to-Sensor Hookup


Used With 100 Ω platinum resistive thermometer (PRT)
Dimensions 1.5 x 1.5 x 2.7 cm (0.6 x 0.6 x 1.0 in.) for body with prongs
Weight 6 g (0.2 oz)

Current Limiting

Resistance 10 kΩ
Tolerance ±5% (@ 25°C)
Power Rating 0.25 W

Completion Resistor (bulk metal foil)

Resistance 100 Ω
Tolerance ±0.01% (@ 25°C)
Maximum Temperature Coefficient ±0.8 ppm/°C
Power Rating 0.25 W (@ 70°C)


Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.

Data Loggers

Product Compatible Note
21X (retired)
CR10 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR295X (retired)
CR3000 (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR800 (retired)
CR850 (retired)
CR9000 (retired)
CR9000X (retired)

Measurement and Control

Product Compatible Note
Granite Volt 108
Granite Volt 116

Additional Compatibility Information

Data Logger Considerations

The 4WPB100 uses two adjacent differential analog inputs; the first channel requires an adjacent analog ground channel to accept the "ground prong" of the 4WPB100. Not all data logger terminal strips have this sequence on all channels, so please check your data logger's wiring panel to confirm channel assignments, especially if you plan to use multiple terminal input modules.

Newer CR10X Wiring Panels and the CR10XTCR Thermocouple Cover are deep enough to cover the data logger input channels with a terminal input module attached; older CR10TCRs are not deep enough.


When using CRBasic, the 4WPB100 is measured with the BrHalf4W Instruction followed by the PRT Instruction. When using Edlog, the 4WPB100 is measured with Instruction 9 (Full Bridge w/ Measured Compensation) followed by Instruction 16 (Temperature RTD).

Frequently Asked Questions

Number of FAQs related to 4WPB100: 3

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  1. Only one 4WPB100 is needed to measure the internal PRT in the radiometer.

  2. The CR1000 requires a 4WPB100 to measure the internal PRT. (Data loggers such as the CR3000 and CR5000 have the necessary PRT bridge module built in to measure the PRT.) Note that the CNR4-L also includes an internal thermistor, which can be directly measured by the CR1000. Because of this, when using a CR1000, Campbell Scientific typically recommends monitoring the internal temperature of the CNR4-L using its internal thermistor instead of the PRT. 

  3. The 4WPB100, 4WPB1K, and 4WHB10K terminal input modules can be used instead of the 3WHB10K module. However, ensure that the jumper is installed between the ground side of the sensor and the low input of the second channel to maintain the four-wire accuracy.

Listed Under

Common Accessory for the following products:

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