Allen-Bradley 1771-OB 12-24 Volt DC Output Module

Allen-Bradley 1771-OB is an 8-channel DC output module for PLC-5/SLC-500 controllers that delivers 12–24 V DC outputs to field devices such as relays, solenoids, lamps, or indicators. Each output is rated up to 1.5 A, with a total module current limit of 8 A. The module supports a DC operating range of 10–27 V and can handle surge currents up to 4 A per channel for 1 ms (repeatable every 1 s). Off-state leakage is 1 mA per output at 27 V, while on-state voltage drop is up to 2 V. Turn-on and turn-off delays are around 10 ms. Maximum power dissipation is listed as 16.9 W for the module. The 1771-OB plugs into a 1771 I/O chassis and is typically wired with a field wiring arm such as the 1771-WA for reliable connections. This DC output module is part of the legacy 1771 I/O family used with older PLC-5/SLC-500 installations to drive discrete DC loads.