Product Overview

The Allen-Bradley 1785-V40V is a specialized VMEbus-based programmable controller that bridges the gap between high-performance computing and industrial automation. As an integral part of the "VME PLC-5" family, this processor is designed to reside directly within a 6U VMEbus chassis (ANSI/IEEE 1014-1987) rather than a traditional 1771 I/O rack. This unique architecture allows industrial computers and VME-based systems to execute standard PLC-5 ladder logic and manage complex industrial processes while maintaining high-speed access to the VME backplane resources.

By integrating the proven reliability of the PLC-5 instruction set into a VME environment, the 1785-V40V serves as a powerful solution for applications requiring high-speed data acquisition, sophisticated mathematical calculations, and seamless multi-processor coordination. It is particularly effective in high-end motion control, aerospace testing, and complex simulation environments.

VMEbus Integration and Logic Performance

The 1785-V40V functions as a dual-role interface, capable of acting as both a Bus Master and a Bus Slave to maximize system interoperability.

• Dual-Role Functionality: In Master mode, the processor can initiate data transfers and control other VME modules. In Slave mode, the 1785-V40V acts as shared memory, allowing other host CPUs in the chassis to read its status or write control variables.

• High-Density Memory: Equipped with 48,000 words of battery-backed SRAM, providing ample space for extensive control programs, data tables, and historical logging.

• Scalable Multi-Processing: The architecture supports the installation of up to eight 1785-V40V cards within a single VMEbus chassis, enabling massive parallel processing for distributed control tasks.

• Extended I/O Addressing: Supports a total of 1920 I/O points and 1920 analog points, ensuring compatibility with large-scale industrial field device deployments.

Technical Specifications

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model Number: 1785-V40V

• Module Type: VMEbus PLC-5 Processor

• Form Factor: 6U Single-slot (Standard VMEbus Mechanical Specs)

• User Memory: 48K Words (SRAM)

• Communication Ports: 4 DH+/Remote I/O (RIO) Channels; 1 RS-232C Serial Port

• I/O Capacity: 1920 Digital I/O; 1920 Analog I/O

• VME Compatibility: Master/Slave A24:D16, D32

• Backplane Current Draw: Approx. 3.5A @ 5V DC

• Operating Temperature: 0°C to 60°C (32°F to 140°F)

• Weight: 0.72 kg (1.59 lbs)

• Dimentions: 4.1x18.8x26.2cm

Connectivity and Industrial Protocols

The 1785-V40V maintains full compatibility with the Allen-Bradley communication ecosystem, ensuring it can control legacy field hardware while communicating with modern supervisory systems.

• DH+ and Remote I/O: The four integrated channels allow the processor to act as a scanner for 1771-series I/O or communicate with other PLC-5 and SLC 500 controllers via Data Highway Plus.

• Serial Interface: The RS-232C port facilitates local programming via a PC, as well as connections to peripheral devices like barcode readers, weight scales, or operator interfaces.

• Software Compatibility: Fully programmable using standard RSLogix 5 software, ensuring that existing PLC-5 code can be migrated to the VME platform with minimal modification.