Excellent PLC
Product Introduction
The Allen-Bradley 1771-A4B 16 Slot I/O Chassis is a large-capacity modular rack designed for PLC-5 and 1771 series control systems developed by Allen-Bradley. The chassis functions as the primary mounting platform for PLC I/O modules, providing the structural framework and electrical backplane necessary for communication and power distribution across the automation system.
With sixteen available module slots, the 1771-A4B chassis is typically used in medium and large industrial control systems where numerous input, output, and communication modules must be installed within a single rack. The integrated backplane distributes power and communication signals between installed modules and the system processor, ensuring coordinated operation of the entire PLC system.
The open-style rack design allows the chassis to be installed inside industrial control cabinets where it can be combined with PLC processors, power supplies, and various I/O modules. This structure makes the system easier to maintain, expand, and reconfigure as automation requirements change.
The 1771-A4B chassis is commonly used in manufacturing automation, process industries, and large machine control systems. By supporting multiple I/O modules within a single rack, it provides engineers with a scalable foundation for building reliable PLC-based automation architectures.
Product Specifications
| Parameter | Description |
|---|---|
| Product Name | Allen-Bradley 1771-A4B 16 Slot I/O Chassis |
| Manufacturer | Allen-Bradley |
| Series | 1771 PLC-5 I/O System |
| Product Type | Rack / I/O Chassis |
| Number of Slots | 16 slots |
| Backplane Current Rating | 24 A |
| Backplane Voltage | 5.25 VDC |
| Enclosure Type | Open style |
| Mounting | Panel mounting in control cabinet |
| Backplane Function | Provides electrical connection and communication path between installed modules |
| System Compatibility | Designed for PLC-5 and 1771 series I/O modules |
| Dimensions | 610 × 315 × 193 mm |
| Weight | 6.7 kg |
Applications
● Large PLC Control Systems
Used as the main rack for PLC-5 automation systems where multiple I/O modules must be installed in a centralized structure.
● Manufacturing Automation Lines
Installed in factory control cabinets to support sensors, actuators, and control devices used in production equipment.
● Process Industry Facilities
Common in industries such as chemical processing, power generation, and water treatment where many I/O signals must be managed by a PLC system.
● Machine Control Systems
Provides organized installation of digital and analog I/O modules used in complex machinery and automated equipment.
● Automation System Expansion
Suitable for expanding existing PLC-5 systems by adding additional I/O capacity within a single rack.
Advantages
● Large Module Capacity
The sixteen-slot configuration allows installation of many I/O modules, making it suitable for large automation systems.
● Reliable Backplane Communication
The integrated backplane distributes both data signals and power to installed modules, ensuring stable system operation.
● High Current Capability
With a 24-amp backplane current rating, the chassis can support multiple high-power I/O modules operating simultaneously.
● Industrial-Grade Mechanical Design
The rugged rack structure ensures reliable operation in industrial control cabinets and manufacturing environments.
● Flexible System Configuration
Supports a wide range of 1771 series modules, allowing engineers to design customized automation solutions.
● Scalable PLC Architecture
The chassis can serve as part of a larger PLC-5 system with multiple racks and distributed I/O modules.
