Allen-Bradley 1785-V80B VME Processor Card

The Allen-Bradley 1785-V80B functions as a high-performance bridge between standard PLC-5 control and VMEbus architecture. This processor integrates directly into VMEbus systems to facilitate high-speed data exchange with specialized co-processors. It eliminates the need for external bridge hardware while maintaining the robust instruction set of the PLC-5/40 series. Unlike standard chassis-based processors, this module leverages the VMEbus backplane for peer-to-peer communication.

Technical Specifications

• Processor Series: PLC-5 Enhanced (VMEbus Version)
• Total User Memory: 100,000 Words
• Maximum I/O Capacity: 2,944 Total Points
• Logic Execution Speed: 0.5 ms per 1K words (Bit Logic)
• Communication Ports: 4 Configurable (DH+ or Universal Remote I/O)
• Serial Interface: RS-232-C (DF1 Protocol support)
• VME Compatibility: C.1 Specification compliant
• Maximum Remote Racks: 23 Physical Racks
• Typical Current Draw: 3.4A at 5V DC

Operational Capabilities

The module executes ladder logic programs with high efficiency to ensure rapid system updates. Users can configure the four onboard ports for Data Highway Plus or Remote I/O functionality. This flexibility allows the unit to manage up to 92 remote chassis across a distributed network. It utilizes a dedicated VME status file for real-time monitoring of backplane health.

Enhanced MSG instructions enable the processor to handle complex VMEbus data transfers and hardware interrupts. The internal memory structure supports up to 32,000 words per individual data table file. This capacity accommodates large-scale analog applications and extensive recipe storage requirements.

Integration and Programming

Engineers can program the 1785-V80B through three distinct pathways to simplify commissioning. These options include DH+ networks, local serial connections, or direct VMEbus backplane access. The module maintains compatibility with existing PLC-5 code to reduce engineering overhead during system upgrades. It operates without EEPROM modules and relies on high-speed internal RAM for program execution.