Description The Allen-Bradley 1771-DB is a communication module designed for PLC-5 systems, providing serial and DH-485 connectivity for industrial applications. It enables data exchange through RS-232-C, RS-422-A, RS-485, and DH-485 ports while supporting BASIC and C program execution directly on the module. With built-in processing capability and block-transfer communication, it enhances system performance by offloading tasks from the main PLC processor. Technical Specifications Condition New/Never Used Surplus Category PLC Modules Subcategory 1771 Communication Modules Brand Allen-Bradley Manufacturer Rockwell Automation Part Number 1771-DB Module Type Communication Module Description PLC BASIC Module Communication Port Protocols RS-232-C, RS-422-A, RS-485, DH-485 Operation BASIC programs and C programs Communication with PLC Processor Block-Transfer with PLC-5 processor Wiring Arm 1771-WN Module Scan Time 1.3–5 ms Storage Temperature –40 to 185 °F (–40 to 85 °C) Coating Conformal coat Dimensions 3.5 × 6.5 × 2.0 in (89 × 165 × 51 mm) Information About 1771-DB The 1771-DB is a PLC BASIC communication module that integrates seamlessly into 1771 I/O chassis systems. It supports multiple serial standards, including RS-232-C, RS-422-A, RS-485, and DH-485, allowing communication with a broad range of external devices such as printers, modems, computers, and third-party controllers. Featuring onboard RAM and program execution capability, the module can perform data handling, parsing, calculation, and report generation independently of the PLC-5 processor. Its block-transfer interface ensures efficient data movement between the processor’s data table and the module’s memory, reducing programming overhead and improving system throughput. Key Features: Multi-Protocol Communication: Supports RS-232-C, RS-422-A, RS-485, and DH-485 for versatile device integration. Independent Program Execution: Runs BASIC and C programs directly on the module to reduce PLC processor load. Block-Transfer Interface: Provides efficient memory exchange with PLC-5 processors for fast communication cycles. Battery-Backed Memory: Includes onboard RAM for storing program logic and application data during power loss. Isolated Communication Ports: 500 VDC isolation improves reliability and protects both module and backplane. Flexible Serial Connectivity: Offers separate ports for serial communication and DH-485 networking. Diagnostic Indicators: Built-in status LEDs simplify monitoring and troubleshooting of communication activity. Compact Form Factor: Occupies a single slot in the 1771 I/O chassis for simple installation. The 1771-DB provides advanced communication and processing capabilities ideal for PLC-5 applications requiring flexible serial integration and independent data handling.
