Overview
The Allen-Bradley 1771-OAD is a discrete AC output module engineered for the PLC-5 family of programmable logic controllers. This 16-point output module operates across a wide voltage range of 10–138 volts AC (47–63 Hz), making it suitable for controlling solenoids, motor starters, indicator lights, and other moderate-voltage AC loads. The module features zero-crossing switching technology, which minimizes electrical stress on connected devices and extends component lifespan. As a surplus/used unit, it offers significant cost savings for replacement and expansion of legacy automation systems.
Key Features
- 16 Programmable Output Channels: Individual control of each discrete output point
- Wide Operating Voltage Range: 10–138V AC at 47–63 Hz frequency
- Zero-Crossing Switching: Reduces inrush current and stress on loads
- Individual Status Indicators: LED indicators on each channel for troubleshooting and verification
- Field-Wiring Arm Compatible: Compatible with 1771-WH and 1771-WHF wiring arms
- Removal Under Power (RIUP): Module can be replaced without disconnecting field wiring
Technical Specifications
- Number of Outputs: 16 discrete AC channels
- Voltage Rating: 10–138V AC (also labeled 12–120V AC on some variants)
- Frequency: 47–63 Hz
- Output Current per Channel: 2 A maximum
- Maximum Module Load: 8 A pilot duty (total)
- Minimum Load Current: 5 mA
- Maximum OFF-State Leakage: 3.0 mA @ 138V AC
- Backplane Current: 295 mA @ 5V DC
- Power Dissipation: 1.5–13 W
- Series: Series B / Series C
- Fusing: Individual output fuses, accessible via front cover
Typical Applications
- Control of AC solenoid valves in fluid power systems
- Drive small-to-medium motor starters (up to Size 4)
- Operation of indicator lamps and pilot lights
- Switching of heating elements and resistive loads
- General discrete AC switching in process automation environments
Compatibility & Replacements
Compatible With
- PLC-5 Programmable Logic Controller systems
- 1771-A1B through -A4B I/O chassis
- 1771-AM1 and -AM2 chassis
- 1771-WH field-wiring arm (standard)
- 1771-WHF field-wiring arm (optional fused variant)
- Studio 5000 Logix Designer (with legacy PLC-5 libraries)
Replaces / Drop-In Replacement For
The 1771-OAD Series C /G01 revision directly replaces earlier revisions of the 1771-OAD, including Series B variants, when installed in compatible 1771 chassis. Not compatible with 1771-A1, 1771-A2, or 1771-A4 chassis.
Works With
- PLC-5 ladder logic programming (RS-Logix 5)
- DeviceNet and ControlNet on compatible processors
- Allen-Bradley I/O addressing conventions (16 output bits per module)
- Standard AC field-wiring practices (L1, L2, individual output terminals)
