PLC Boards

1756-OF4

1756-OF4 - 4-Channel ±10 V/0–20 mA AO Module | Allen-Bradley

The Allen-Bradley 1756-OF4 is a four-channel, non-isolated analog output module for the ControlLogix platform, providing ±10 VDC voltage outputs or 0–20 mA current outputs through a 20-pin removable terminal block in an open-style module. An analog output module is an industrial programmable-controller I/O device that converts controller data into continuously variable voltage or current signals. It sits between the ControlLogix controller and field equipment in the hierarchy of industrial automation: PLC system, programmable automation controller, I/O module, and analog output interface. The module provides four selectable outputs, 15-bit resolution, scaling, calibration, ramping, clamping, configurable program and fault states, and open-circuit detection for current outputs. Verified distributor data identifies 0–20 mA current operation, ±10 VDC voltage operation, and a 20-pin open-style format. A service-manual source additionally specifies 650 nA per bit across 21 mA for current output and 320 µV per bit across 10.5 V for voltage output. The ControlLogix backplane connection and removable terminal block support modular cabinet installation. Published operating temperature data spans 0°C to 60°C, while the module draws 150 mA at 5.1 VDC or 120 mA at 24 VDC from the backplane. Series B and C hardware has higher power requirements than Series A, an important replacement-planning consideration. Typical uses include proportional control valves, variable-speed drives, positioning equipment, current-loop transmitters, and test systems. Voltage outputs suit drives and positioners accepting bipolar analog commands; current outputs support two-wire process transmitters and provide open-circuit fault detection. Before installation, verify the ControlLogix chassis, controller compatibility, module series, terminal-block wiring, output mode, grounding, and field-device loop resistance. Keep voltage and current wiring distinct and configure output behavior for safe process states during controller faults or disconnects. This page consolidates verified manufacturer and distributor specifications, sourcing links, technical comparisons, and engineering guidance. Because no verified drop-in replacement was found, it does not present unverified substitutes or cross-brand modules as pin-compatible alternatives.