Overview
The Allen-Bradley 1771-KA2 is a Data Highway station interface module designed for Bulletin 1772 PLC-2 family processors. This communication adapter enables memory data exchange between PLC-2 processors and connects individual processors to the Data Highway network, creating a distributed automation system. The 1771-KA2 is essential for legacy PLC-2 installations requiring inter-processor communication and remote programming capabilities.
Key Features
- Multi-Channel Communication: Three independent ports (Program Interface, Data Highway, and Processor) with optimized baud rates for different communication needs
- Daisy-Chain Capability: Second module “daisy chain” configuration enables expanded network topologies
- Remote Data Table Modification: Allows remote resizing of processor data table without manual intervention
- Automatic Error Checking: Built-in data validation and self-checking diagnostics with LED status indicators
- Ladder Diagram Programming: Integrates seamlessly with PLC-2 ladder logic for simplified commissioning
- Memory Write Protection: Programmable and switch-selectable memory protection through software or hardware settings
Technical Specifications
- Series: PLC-2 Family (1772 Compatible)
- Program Interface Port Speed: 9.6 kilobaud
- Data Highway Port Speed: 57.6 kilobaud
- Processor Port Speed: 91.2 kilobaud
- Power Supply Requirement: 5V DC at 1.2A maximum
- Operating Temperature: 0–60 °C (32–140 °F)
- Relative Humidity: 5% to 95% (without condensation)
- Operating Shock: 30g
- Chassis Mounting: 1771 I/O chassis (any slot except furthest left)
- Connector Key Bands: Pins 4–6 (lower) and 22–24 (upper) for correct installation
- Network Capacity: Up to 64 programmable devices on single Data Highway (10,000 feet maximum cable run)
Typical Applications
The 1771-KA2 is commonly deployed in legacy manufacturing environments where PLC-2 processors form the backbone of automation control. Applications include:
- Multi-processor data synchronization in distributed control systems
- Remote program upload/download via Data Highway network
- Integration of PLC-2 processors into larger industrial networks
- Maintenance and expansion of installed PLC-2 automation systems
- Communication between master and satellite PLC-2 processors in production lines
Compatibility & Replacements
The 1771-KA2 is compatible with Bulletin 1772 PLC-2 family processors including PLC-2 (1772-LR), PLC-2/20 (1772-LP1, -LP2), PLC-2/30 (1772-LN1, -LN2, -LN3), Mini-PLC-2/05 (1772-LS, -LSP), and Mini-PLC-2/15 (1772-LV). Compatible power supplies include 1771-P1, -P2, -P3, -P4, and -P5 series. For modern PLC-5 or ControlLogix systems, Rockwell Automation offers newer communication modules such as the 1784-U2DHP/A or comparable ControlLogix Ethernet adapters, though direct architectural replacement is not possible due to platform differences. This module represents a legacy platform; newer Allen-Bradley systems use Ethernet-based communication.
