The Allen Bradley 1771-ALX is a PLC-5 local I/O adapter module used to connect multiple 1771 I/O chassis within a distributed local architecture. It allows PLC-5 processors to control extended I/O racks through a dedicated high-speed local I/O communication link.
The module is typically installed in the left-most slot of the chassis and is designed for large-scale automation systems where multiple control cabinets are physically separated but logically unified.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Allen Bradley (Rockwell Automation) |
| Catalog Number | 1771-ALX |
| Module Type | Local I/O Adapter Module |
| System Family | PLC-5 / 1771 I/O |
| Function | Multi-chassis local I/O expansion |
| Communication Type | Parallel Local I/O link |
| Max Cable Distance | Up to 30 m (98.4 ft) |
| Cable Types | 1771-CX1 / CX2 / CX5 |
| Termination | 1771-CXT required |
| Backplane Current | ~1.2 A @ 5 V DC |
| Power Dissipation | ~6 W |
| Mounting Position | Left-most slot |
| Operating Temperature | 0°C to 60°C |
| Storage Temperature | -40°C to 85°C |
| Weight | ~0.55 kg |
| Dimensions (L×W×H) | 118 mm × 35 mm × 87 mm |
System Function Overview
The 1771-ALX acts as a local rack expansion interface, enabling multiple PLC-5 I/O chassis to behave as a unified control system.
Key roles include:
- Local I/O rack synchronization
- High-speed parallel communication between chassis
- Distributed cabinet architecture support
- Expansion of PLC-5 I/O capacity without full redesign
Recommended Related Modules
| Model | Function |
|---|---|
| 1771-A3B1 | 12-slot I/O chassis |
| 1771-A4B | 16-slot I/O chassis |
| 1771-ASB | Remote I/O adapter |
| 1771-IBD | Digital input module |
| 1771-OBD | Digital output module |
| 1771-P7 | Power supply module |
Common PLC-5 System Components
| Model | Role |
|---|---|
| 1785-L40B | PLC-5 processor |
| 1771-SN | I/O scanner module |
| 1771-DH | Data Highway communication module |
| 1771-IFE | Analog input module |
| 1771-OW | Relay output module |
