Allen-Bradley 1756-OF4 Analog Output Module 4-Channel

The Allen-Bradley 1756-OF4 is a four‑channel analog output module for ControlLogix backplanes that provides four configurable outputs in a single slot for controlling analog actuators and process equipment. Each channel can be set as either a -10 to +10 V voltage output or a 4–20 mA current output, driven by a true 15‑bit DAC with separate resolutions (voltage ~320 µV/bit over a 10.5 V span; current ~650 nA/bit over a 21 mA span). Key performance figures include a settling time under 2 ms to 95% of final value with resistive loads and calibrated accuracy better than 0.05% of range (4–21 mA or -10.4 to 10.4 V). The module features 250 V continuous isolation between the output backplane and channels, with no isolation between individual channels. Backplane power requirements are 5.1 V up to 150 mA or 24 V up to 210 mA (total backplane power around 5.8 W), and the device dissipates about 3.7 W. Open‑circuit detection, 24 V DC overvoltage protection, and short‑circuit protection electronically limited to 21 mA or less enhance reliability. Field wiring is through removable terminal blocks (1756‑TBNH or 1756‑TBSH), and the module occupies a standard 1756 slot. In applications, it provides precise, independently configurable analog outputs for ControlLogix systems, suitable for interfacing with analog transducers, valves, or actuators in automation and process control environments.