Allen Bradley 1771-OA 8-Channel AC Output Module

The Allen Bradley 1771-OA, also cataloged as the 1771-OA Output Module, operates as a dedicated hardware component for discrete signal actuation within PLC-5 I/O chassis platforms.

Hardware Specifications

Profinet / EtherNet/IP Deterministic Networks

The 1771-OA integrates into the PLC-5 system architecture to facilitate discrete signal execution via the 1771 I/O chassis backplane. The module translates backplane bus commands into 120 VAC outputs, with deterministic timing characteristics defined by an Off-state signal delay of 45 (+/- 15) ms. Firmware flash compatibility is intrinsically linked to the PLC-5 processor scan cycle. I/O density scaling is managed by the rack configuration, with the module occupying a single slot in the chassis. Consistent backplane bus communication velocity is maintained through the standard 1771 backplane interface, ensuring reliable status reporting to the CPU.

Frequently Asked Questions

Q: Can the 1771-OA be used with DC loads?

A: No. The 1771-OA is specifically designed for 92 - 138 VAC applications. Utilizing this module with DC loads will prevent proper turn-off of the triac output, potentially resulting in load damage or module failure.

Q: What are the keying requirements for this module?

A: The module must be keyed to prevent installation in incorrect chassis slots. The field wiring arm interface must be keyed between pins 4 and 6, and between pins 12 and 14 to match the module configuration.

Field Installation Guidelines

1. Chassis Preparation: Power down the 1771 I/O chassis before module insertion. Configure the backplane keying tabs to match the 4-6 and 12-14 positions specified for the 1771-OA.
2. Wiring Arm Installation: Attach the 1771-WA or 1771-WH wiring arm to the module. Ensure the arm is locked into the operating position.
3. Torque Specifications: Tighten all wiring arm terminal screws to a torque of 7-9 inch-pounds. Insufficient torque can cause high-resistance connections and potential heat build-up.
4. Load Circuitry: Ensure that the total continuous current for the module does not exceed 6 Amperes, and that no individual channel exceeds 1.5 Amperes.
5. Signal Verification: Confirm output status using the diagnostic indicators on the module front panel. Verify that AC load leakage currents do not affect the state of high-impedance input devices connected to the output.