Allen-Bradley 1756-IH16I 16-Point Input Module

The Allen-Bradley 1756-IH16I is a ControlLogix 16-channel isolated-input module that accepts 90–146 VDC signals and presents 16 independently isolated digital inputs to the 1756 backplane. It is designed to monitor DC sensor circuits with nominal 125 VDC input levels while preserving input‑to‑input and input‑to‑backplane isolation to protect the controller from wiring faults and transients. Key specs include 16 input channels with an input impedance of up to 48.67 kΩ at 146 V DC, an on‑state current of up to 3 mA per channel (at 146 V DC) and an off‑state current of ≤0.8 mA, and a continuous isolation rating of 250 V between inputs and the backplane (with routine testing at higher AC levels). The module offers configurable cyclic update times from 200 µs to 750 ms, along with input time stamping of ±200 µs to support precise event logging in high‑speed processes. It uses a removable terminal block housing (commonly 1756-TBCH or 1756-TBS6H) for field wiring and is electronically keyable with software configuration to help prevent missertion in the rack. Designed for open-style mounting with a slot width of 1 and North American temperature coding (T4), the 1756-IH16I integrates into standard ControlLogix I/O specifications and is compatible with Rockwell Automation’s 1756 I/O chassis ecosystem for DC digital inputs. This module is suited for industrial sensing where rugged, voltage‑level DC inputs must be isolated from the controller, while providing reliable, discrete state information to the ControlLogix processor.