The Allen Bradley 1771-IAD is a PLC-5 series AC digital input module designed for the 1771 I/O platform. It is used to interface AC field devices such as push buttons, limit switches, selector switches, and relay contacts with PLC-5 control systems.
This module converts AC input signals into digital logic signals for processing by the PLC processor and is commonly used in industrial control panels requiring reliable discrete signal acquisition.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Allen Bradley (Rockwell Automation) |
| Catalog Number | 1771-IAD |
| Module Type | AC Digital Input Module |
| System Family | PLC-5 / 1771 I/O |
| Input Voltage Range | 120V AC nominal (typical variant) |
| Input Channels | 16 points |
| Input Type | Isolated AC inputs |
| On-State Voltage | Typically 79–132V AC |
| Off-State Voltage | ≤ 30V AC |
| Backplane Current Draw | ~0.35 A @ 5 V DC |
| Input Frequency | 47–63 Hz |
| Response Time | Standard industrial filtering |
| Isolation | Optical isolation per group |
| Mounting Type | 1771 chassis slot |
| Operating Temperature | 0°C to 60°C |
| Storage Temperature | -40°C to 85°C |
| Weight | ~0.45 kg |
| Dimensions (L×W×H) | 118 mm × 35 mm × 87 mm |
System Function Overview
The 1771-IAD module is responsible for reading AC field device signals and transmitting them to the PLC-5 processor via the backplane.
Core functions include:
- AC signal acquisition from field devices
- Conversion of AC input to PLC digital logic
- Electrical isolation between field and control system
- Integration into PLC-5 control architecture
- Support for industrial switching devices
It is widely used in discrete manufacturing and process automation systems.
Recommended Related Modules
| Model | Function |
|---|---|
| 1771-IBD | DC digital input module |
| 1771-OBD | Digital output module |
| 1771-OWNA | Relay output module |
| 1771-IFE | Analog input module |
| 1771-P7 | Chassis power supply |
| 1771-ASB | Remote I/O adapter |
Common PLC-5 System Modules
| Model | Role |
|---|---|
| 1785-L40B | PLC-5 processor |
| 1771-A4B | 16-slot I/O chassis |
| 1771-DMC | Data Highway communication module |
| 1771-SN | I/O scanner module |
| 1771-DH | Network communication module |
