The Allen-Bradley 1756-IRT8I, also cataloged as the 1756-IRT8I RTD Thermocouple Input Module, operates as a dedicated hardware component for isolated temperature signal acquisition within ControlLogix automation platforms.

Model Reference

The Allen-Bradley 1756-IRT8I is an 8-channel isolated analog input module designed for RTD, thermocouple, and millivolt signal measurement. It provides temperature data conversion and transfers processed values through the ControlLogix backplane communication system.

Hardware Specifications

ControlLogix Temperature Measurement Characteristics

The 1756-IRT8I integrates with ControlLogix chassis architecture to process temperature-related analog signals from industrial sensors. The isolated input design provides channel separation for RTD, thermocouple, and millivolt measurements.

Allen-Bradley ControlLogix modules use deterministic backplane communication for data exchange between I/O modules and Logix controllers. The 1756-IRT8I requires compatible firmware flash compatibility, module configuration, and controller recognition settings before operation.

Signal Processing and Isolation Capability

The module provides eight isolated input channels with support for multiple thermocouple types and RTD measurement applications. The IEEE 32-bit floating point data format allows processed temperature values to be transferred directly to ControlLogix controller applications.

The 250 V continuous isolation rating separates individual field measurement circuits from the module electronics and helps maintain signal integrity in multi-channel temperature monitoring applications.

Ordering Information

• 1 x Allen-Bradley 1756-IRT8I ControlLogix 8 Point RTD Thermocouple Input Module
• 1 x ControlLogix compatible input module assembly
• Standard module identification label and terminal interface
• ControlLogix chassis, power supply, and field sensors are not included unless separately specified

Installation Guidelines

• Confirm the module revision and ControlLogix chassis compatibility before installation.
• Select the correct input configuration for RTD, thermocouple, or millivolt signals.
• Use shielded sensor wiring where required by the installation environment.
• Maintain separation between temperature signal cables and high-voltage power conductors.
• Verify thermocouple polarity and sensor wiring before controller startup.
• Check module diagnostics and input values after commissioning.

Firmware and Network Compatibility

The 1756-IRT8I operates within the ControlLogix hardware ecosystem where module firmware, Logix controller configuration, and electronic keying settings must be matched. Correct firmware compatibility ensures proper temperature data exchange through the ControlLogix backplane.

Frequently Asked Questions

• What signals does the 1756-IRT8I support?

  The module supports isolated RTD, thermocouple, and millivolt input signals through eight independent channels.

• How many temperature input channels are available?

  The module provides 8 isolated input channels for temperature measurement applications.

• Which thermocouple types are compatible?

  Supported types include B, C, D, E, J, K, N, R, S, T, and TXK/XK (L).

• What is the module power dissipation?

  The maximum power dissipation is 4.6 W during operation.

• What is the backplane current requirement?

  The module requires 200 mA at 5.1 VDC and 150 mA at 24 VDC.

• Does the module provide channel isolation?

  Yes. The module provides isolated input channels with 250 V continuous isolation rating.

• What data format is used by the module?

  The module transfers measurement data using IEEE 32-bit floating point format.

• Does the module require configuration before use?

  Yes. Input type selection, controller configuration, and module parameters must be set before operation.