Product Overview

The 1756-IR6I/A​ is a 6-channel, individually isolated RTD (resistance temperature detector) input module manufactured by Allen-Bradley, a brand of Rockwell Automation, and is a high-performance member of the Bulletin 1756 ControlLogix family of programmable automation controllers. Designed to bring precise temperature measurements from RTD sensors directly into a ControlLogix controller, the 1756-IR6I/A​ converts the resistance of platinum, nickel, and copper sensing elements into scaled engineering data with 21-bit resolution and presents it to the user program as a temperature value rather than a raw count. Each of the six channels is isolated from the backplane and from every other channel, making the module uniquely capable of measuring sensors that do not share a common reference — a condition that is the norm rather than the exception in electrically noisy industrial environments.The architecture of the 1756-IR6I/A​ is built around high-resolution analog-to-digital conversion combined with configurable excitation and lead-wire compensation. The module supports Pt100, Pt1000, nickel, and copper RTDs across their full measurement spans, and it automatically compensates for 2-wire, 3-wire, and 4-wire lead configurations so that the resistance of the sensor leads does not appear as an error in the temperature reading. With a typical accuracy of 0.1 °C and 21 bits of resolution, the 1756-IR6I/A​ resolves temperature changes far smaller than the quantization steps of a lower-resolution card, allowing PID loops to hold setpoint without the hunting and overshoot that coarse analog inputs impose. Drawing 300 mA from the 5.1 V DC backplane and dissipating 3.7 W, the module occupies a single chassis slot and carries the same open-style enclosure and 0–60 °C rating as the rest of the ControlLogix family. Series A denotes the original hardware revision, and like all ControlLogix I/O, the 1756-IR6I/A​ requires a separately ordered removable terminal block — the 1756-TBCH screw-clamp or 1756-TBS6H spring-clamp housing — to terminate the sensor wiring.

Technical Specifications