1771-OAN | Allen-Bradley Output Module

The 1771-OAN is a 32-point Digital AC Output Module designed for use with Allen-Bradley PLC-5 and Mini-PLC systems. It functions as a source output module, delivering a positive voltage path to connected sinking input devices, such as relays or actuators. It supports a wide AC voltage range of 80 to 265 VAC, and is engineered to drive field devices operating at line voltage. The module is divided into four groups of eight outputs, allowing for logical signal segmentation. Its robust design makes it suitable for heavy-duty industrial applications where discrete AC control is needed. This module is ideal for applications that require reliable switching of high-voltage AC loads directly from the PLC system.

Yes, the 1771-OAN is compatible with Allen-Bradley Mini-PLC controllers such as the 2/02, 2/16, 2/17, and the PLC-5/15. These legacy controllers use the same chassis and I/O bus as the 1771 modules. The module connects directly into the I/O chassis and interfaces with the processor over the backplane. When using with Mini-PLC systems, attention must be given to chassis power requirements and addressing limitations. Integration with these systems enables legacy equipment to continue operating effectively with modernized maintenance procedures. This compatibility is key for facilities maintaining long-running automation infrastructure.

Yes, the 1771-OAN is rated for operation up to 60°C, but with reduced current capacity at higher temperatures. Specifically, output current per point drops from 1 A at 30°C to 0.3 A at 60°C, with similar reductions across group and total current ratings. These de-ratings are necessary to prevent overheating and ensure the longevity of internal components. If installed in a cabinet with limited airflow, forced ventilation or heat shielding may be required. The module dissipates approximately 55.4 BTU/hour, which contributes to the overall thermal load in the system. Continuous monitoring of ambient conditions can help maintain safe operating limits.

The 1771-OAN provides 32 discrete AC output channels, divided into four electrically isolated groups of eight. This grouping allows for flexible load distribution and simplifies wiring schemes in industrial control panels. Each output channel can independently control a load, such as a solenoid, contactor, or indicator. Grouped configuration also enhances safety by limiting the effects of overcurrent conditions to specific segments. Outputs are optically isolated to protect the PLC from voltage transients. This modularity is ideal for applications requiring dense I/O with individual control over each channel.

The 1771-OAN does not support 2-slot addressing due to limitations in how it maps I/O bits within the PLC memory structure. It must be configured using 1-slot addressing with restrictions, or preferably 1/2-slot addressing, which allows full utilization without memory conflicts. This limitation ensures proper communication between the CPU and the module during scan cycles. When configuring the chassis layout in software, it is crucial to specify the correct slot configuration. Incorrect addressing can lead to partial operation or loss of control over specific output points. Always consult the user manual or PLC-5 addressing guide when integrating the module.