Allen-Bradley 1756-OF4 Analog Output Module

The Allen-Bradley 1756-OF4 is a four-channel analog output module for Rockwell Automation’s ControlLogix I/O backplane. Each of its four channels can be configured to deliver either a voltage signal (up to ±10 V) or a current signal (0–20 mA) to field devices, enabling flexible control of actuators, valves, and analog components in process and automation applications. The module provides high-resolution output: voltage channels are 15‑bit across roughly a 10.5 V span, while current channels are 16‑bit across about a 21 mA span, delivering precise, repeatable control with fine granularity. It uses removable terminal blocks (1756-TBNH or 1756-TBSH) on a 20-pin block for wiring and mounts in a standard ControlLogix chassis. Power dissipation is typically around 3.25 W for four current outputs, with higher dissipation possible at elevated temperatures (up to about 4.9 W), and backplane current requirements of roughly 150 mA at 5 V and 120 mA at 24 V. The 1756-OF4 is commonly employed in industrial automation where multiple analog outputs are needed to drive precision actuators or to implement multi‑point analog control loops within a ControlLogix system.