Description
Allen-Bradley 1771-IDC Isolated AC/DC Input Module PLC-5 1771 Series 120V
The Allen-Bradley 1771-IDC is a 120V Isolated AC/DC Input Module designed for use in Allen-Bradley's 1771 I/O system. It accepts AC or DC field input signals at 120V and communicates discrete input status to the programmable controller through the 1771 backplane. The isolated design provides electrical separation between the field wiring and the controller backplane, protecting the PLC from transient voltages common in industrial field wiring environments.
Specifications & What's Included
- Manufacturer: Allen-Bradley Co., Programmable Controller Systems Division, Cleveland, Ohio
- Catalog Number: 1771-IDC
- Module Type: Isolated AC/DC Input Module
- Input Voltage: 120V AC/DC
- Form Factor: 1771-series single-slot I/O card/module
- Edge Connector: Dual gold-finger card-edge connectors for 1771 backplane
- Terminal Block: Screw-terminal wiring block on front edge (8 input positions visible)
- Input Labeling: Wiring label strip present (Inputs 0A–5B labeled)
- Certifications: UL Listed (File 106V) — listed when used with listed system
- Country of Manufacture: USA
- Compatible Systems: Allen-Bradley PLC-5 processors, 1771 I/O chassis/backplane
- Included: Module only — no cables or accessories
Applications
The Allen-Bradley 1771 I/O system was the standard discrete and analog I/O platform for Allen-Bradley's PLC-5 family of programmable controllers, which were widely deployed in manufacturing automation, process control, material handling, and utilities from the 1970s through the 2000s. The 1771-IDC specifically handles 120V field devices — push buttons, limit switches, proximity sensors, and relay contacts wired at 120V AC or DC — converting their on/off status into digital signals the PLC-5 processor reads through the backplane. The isolated design is particularly suited to environments with noisy field wiring or where ground loops are a concern. Though PLC-5 and 1771 I/O are legacy platforms superseded by Rockwell Automation's ControlLogix and CompactLogix lines, a very large installed base of 1771-based systems remains in service across industrial plants worldwide. Replacement and spare I/O modules like the 1771-IDC are actively sought by maintenance and engineering teams keeping those legacy systems running.
This Allen-Bradley 1771-IDC Isolated AC/DC Input Module has been inspected and appears to be in good condition. It was pulled from a working environment where it was in active use. The module housing is intact with no cracks or broken tabs, the gold edge connectors look clean, and the terminal block and wiring label strip are present. Normal light wear consistent with installed industrial service. Please view our photo set and contact us if you have any questions. Please note: We have multiple units in stock — yours may not be the one shown in the photos, however, it will be similar in condition and function.
Warranty Information
Additional Information
Brand: |
Allen-Bradley |
Model: |
1771-IDC |
MPN: |
1771-IDC |
Type: |
Isolated AC/DC Input Module |
SKU: |
45898 |
Voltage Rating: |
120V AC/DC |
Module Type: |
Isolated AC/DC Input |
Compatible With: |
Allen-Bradley PLC-5, 1771 I/O Backplane |
Series: |
1771 |
Form Factor: |
Card/Module |
Country/Region of Manufacture: |
United States |
Certifications: |
UL Listed (File 106V) |
Manufacturer Division: |
Programmable Controller Systems Division |
Seller Notes: |
Module only; pulled from a working environment. No cables or accessories included. |
Condition Notes: |
Allen-Bradley 1771-IDC 120V Isolated AC/DC Input Module. Inspected, in good condition. Pulled from a working environment. Housing intact, edge connectors clean, terminal block present. Normal wear from installed service. |
