Allen-Bradley 1785-V40L PLC-5 VMEbus Processor Card

Product Overview

The Allen-Bradley 1785-V40L is a specialized, high-reliability VMEbus programmable logic controller (PLC) processor card belonging to the legendary PLC-5® family (specifically refined within Series C, Revision G). Rather than installing into a traditional Allen-Bradley 1771 I/O chassis, the 1785-V40L is custom-engineered to plug directly into a VMEbus (Versatile Backplane Bus) architecture slot.

This hybrid design bridges standard industrial PLC logic processing with VME-based computing systems often found in embedded real-time applications, radar setups, medical imaging, and high-speed defense/aerospace testing grids. By enabling standard Data Highway Plus (DH+) and Remote I/O (RIO) topologies directly out of a VME rack, it acts as a central communication and orchestration node across heterogeneous automation boundaries.

Advanced Capabilities and Functional Benefits

• Seamless VMEbus Integration: Maps standard PLC-5 control data directly into VME memory space, providing high-bandwidth 64 KB VME transfer speeds between the industrial control program and host computer systems.
• Dense Communication Routing: Equipped with 4 Data Highway Plus (DH+) channels and a dedicated Remote I/O (RIO) scanner port, enabling massive network cross-routing without adding separate co-processor cards.
• Message (MG) Data Structuring: Utilizes a highly structured Message (MG) data block setup inside the software configuration to govern deterministic, collision-free data packet transfers between dissimilar controller nodes.
• Multi-Channel Scanning Control: Features independent scan processors on-board—including two channels optimized for remote I/O scanning and one channel dedicated entirely to localized serial protocol management (supporting RS-232, RS-422, and RS-423 standards).
• Comprehensive Diagnostic Array: Outfitted with an extensive layout of localized front-panel LED indicators showing raw Battery Health, Run/Fault statuses, Force conditions, and individual activity/fault matrices for every built-in communication channel.

Technical Specifications

Processing & Memory Performance

• Module Type: VMEbus Slot-Integrated Processor Card
• User Memory Capacity: 48,000 words (Approx. 96 KB)
• VME Bus Speed Capacity: 64 KB
• Direct Addressable I/O Matrix: Supports up to 120 discrete native I/O points
• Remote Rack Expansion Capacity: Scalable up to 15 external 1771 I/O chassis racks
• Required Assembly Component: Requires an external EEPROM/SRAM memory module plug-in for core operational execution.

Physical & Environmental Properties

• Module Form Factor: Standard VMEbus card profile
• Physical Housing Footprint: 4.1 cm (W) x 18.8 cm (H) x 26.2 cm (D)
• Net Hardware Weight: 0.72 kg (Approx. 1.55 lbs)
• Regulatory Conformity: CE Certified for industrial electromagnetic safety
• Country of Origin: United States (USA)
• Product Lifecycle Classification: Vintage Legacy (Discontinued by manufacturer July 31, 2011)

Industrial Applications

• Embedded Military & Aerospace Test Racks: Merging high-speed data acquisition instruments housed in VME enclosures with predictable PLC-5 interlock control.
• Legacy Power Plant Retrofits: Serving as the central data-bridge when linking vintage VME-based turbine control computing stations to modernized 1771 remote I/O valve networks.
• High-Speed Material Handling Coordination: Handling complex sorting conveyor matrices where VME vision hardware must rapidly pass tracking registers down to standard DH+ plant floor controllers.
• Integrated Research Laboratory Automation: Orchestrating complex data streams from diagnostic sensors back to central data logging servers via clean serial-to-VME bus handshaking.