Allen-Bradley 1756-IF8I 8-Channel Analog Input Module

Allen-Bradley 1756-IF8I is an eight-channel isolated analog input module for the ControlLogix 1756 I/O backplane. It accepts both voltage and current signals—10 V ranges (-10 to 10 V, 0 to 10 V, 0 to 5 V) and 0 to 20 mA—while delivering eight individually isolated input points to reduce ground-loop issues in noisy industrial environments. The module provides 24-bit resolution, with 1.49 μV per count for voltage ranges and 2.99 nA per count for current ranges, enabling precise measurements across all channels. Each input is galvanically isolated from the backplane and from other channels, helping protect the controller and simplify field wiring. In terms of power, the device draws 200 mA at 5.1 V on the local supply; from a 24 V supply it can operate in non-sourcing mode (approximately 150 mA) or in sourcing mode (up to 400 mA), with sourcing mode enabling loop-powered sensors on the channels. Total backplane power ranges from 4.6 W in non-sourcing mode to 10.6 W in sourcing mode. The 36-pin interface aligns with standard ControlLogix I/O connections, and the eight isolated inputs are suitable for interfacing a mix of voltage and 4–20 mA transmitters. Designed for use with compatible ControlLogix controllers, this module helps engineers scale analog measurement infrastructure while maintaining signal integrity across rugged industrial environments.