The Allen-Bradley 1771-OAD, also cataloged as the 1771OAD Digital Output Module, operates as a dedicated hardware component for switching AC field devices through 16 discrete output channels within PLC-5 I/O chassis platforms.

Model Configuration Reference

The 1771-OAD is a PLC-5 AC digital output module providing sixteen output points for controlling AC loads. The module uses solid-state triac output technology with zero-crossing switching characteristics for AC voltage control applications.

Hardware Specifications

PLC-5 Backplane Integration

The 1771-OAD receives operating power through the Allen-Bradley 1771 I/O chassis backplane. The module communicates output status through the PLC-5 controller architecture and provides discrete AC switching functions for connected field devices.

The module is compatible with 1771 I/O chassis configurations except 1771-A1, 1771-A2, and 1771-A4 chassis models. Proper module group configuration is required when using 2-slot addressing to prevent conflicts with other output modules or single card block transfer modules.

Solid-State AC Switching Characteristics

The 1771-OAD uses triac-based output switching with zero-crossing technology. The output device switches when the AC waveform reaches a low voltage point, reducing electrical stress caused by inrush current on connected loads.

The module supports AC loads within the specified voltage and current range. High impedance loads such as LED indicators or relay coils may require parallel leakage compensation components because triac outputs maintain a small off-state leakage current.

Industrial Control Network and I/O Density Scaling

Allen-Bradley PLC-5 systems use modular 1771 I/O architecture for distributed field signal handling. The 1771-OAD expands discrete output capacity by providing sixteen independent AC output channels within a single chassis slot.

The module operates through the PLC-5 backplane communication structure where I/O density scaling depends on chassis layout, addressing mode, controller capacity, and installed module quantity.

Ordering Info

• 1 x Allen-Bradley 1771-OAD PLC-5 16 Point AC Digital Output Module
• 1 x Module identification label
• 1 x Standard terminal interface compatibility
• Field wiring arm, PLC-5 chassis, power supply, and external wiring components are not included unless separately specified

Field Installation Guidelines

Module Installation

• Verify PLC-5 chassis compatibility before mounting the module.
• Confirm that the chassis model is not 1771-A1, 1771-A2, or 1771-A4.
• Install the module with the correct keying position and secure chassis connection.

Field Wiring

• Connect AC load wiring according to the assigned output terminal configuration.
• Maintain separation between AC power wiring and low-level signal wiring.
• Confirm load current requirements before connecting field devices.

Leakage Current Considerations

• Review connected load characteristics when using LED lamps or high impedance devices.
• Install appropriate leakage compensation components when required by the application.
• Verify output status indicators after field wiring completion.

Frequently Asked Questions

• What type of outputs does the 1771-OAD provide?

  The 1771-OAD provides sixteen AC solid-state digital output channels using triac switching technology for PLC-5 control applications.

• What voltage range does the module support?

  The module supports AC output operation from 10 to 138 VAC at frequencies between 47 and 63 Hz.

• What is the maximum output current capability?

  Each output channel supports up to 2 A, with the total module current limited to 8 A.

• What is the required backplane current?

  The module requires 295 mA from the 1771 I/O chassis backplane power supply.

• Can the module control LED loads directly?

  LED or high impedance loads may be affected by triac leakage current and may require parallel compensation resistance.

• Which chassis are compatible with the 1771-OAD?

  The module is compatible with most 1771 I/O chassis except 1771-A1, 1771-A2, and 1771-A4 chassis models.

• Does the module provide electrical isolation?

  The module uses solid-state AC output switching. Field circuit isolation depends on the module design and connected wiring configuration.

• What protection features are included?

  The module includes fuse protection and status indication functions for output monitoring and fuse-blown detection.