Allen Bradley 1794-CJC2 FLEX I/O Cold Junction Compensation Kit

Product Overview

The Allen Bradley 1794-CJC2 provides the critical thermal reference required for accurate thermocouple measurements within the FLEX I/O platform. This kit consists of two high-precision Cold Junction Compensation (CJC) thermistors that plug directly into the terminal base of a thermocouple input module. It eliminates measurement errors caused by the junction of dissimilar metals at the terminal block, ensuring the PLC receives a true temperature reading. We supply this kit as 100% Brand New and Original, ensuring your process control loops maintain factory-calibrated accuracy.

Technical Specifications

The 1794-CJC2 kit utilizes specialized thermistor technology to stabilize temperature data:

Engineering Advantages

The 1794-CJC2 kit optimizes thermal monitoring in complex distributed I/O environments:

• Hardware-Based Error Correction: These sensors measure the exact temperature of the terminal screws where the thermocouple wires connect. This data allows the input module to mathematically subtract the ambient thermal voltage, leaving only the actual process temperature.

• Rugged Environmental Resilience: The sensors operate reliably across an extended temperature range from -20°C to +70°C. This makes the kit suitable for remote I/O cabinets located near furnaces or in unconditioned outdoor enclosures.

• Seamless Terminal Integration: The design allows for rapid installation into the 1794-TBN or 1794-TB3 terminal bases. The sensors seat firmly into designated slots, preventing accidental displacement during high-vibration machine operation.

• Support for Extreme Environments: Compatibility with FLEX XT (Extended Temperature) and FLEX EX (Hazardous Location) modules ensures that critical temperature safety interlocks function correctly in the most demanding industrial sectors.

FAQs

• How many 1794-CJC2 kits do I need for a single 8-channel module?

  Each 1794-CJC2 kit contains two sensors. You require exactly one kit (two sensors) per thermocouple module. Typically, you install one sensor on each side of the terminal base to provide a balanced thermal reference for all input channels.

• Does this kit require separate wiring to the PLC?

  No. The 1794-CJC2 sensors connect directly into the dedicated terminals on the 1794 terminal base. The I/O module automatically detects the thermistor resistance through the backplane connection, requiring no additional field wiring or external power.

• Can I use the 1794-CJC2 with other I/O brands?

  No. This kit features a specific form factor and resistance curve designed exclusively for Allen Bradley FLEX I/O thermocouple modules. Using third-party sensors will result in significant temperature offset errors or module diagnostic faults.

• What happens if a CJC sensor fails or is missing?

  The thermocouple module detects the open circuit and flags a "CJC Open" fault in the controller. Without these sensors, the module cannot perform the necessary cold-junction compensation, and your temperature readings will drift significantly as the ambient temperature inside the control cabinet changes.