Features:
- Bridge Between AC Power Input and PLC-5 Rack Backplane
- Integrates AC/DC Power Conversion with DH+ Network Communication
- Functions in Coordination with PLC-5 Family Processors and I/O Modules
The Allen-Bradley 1785-LT3 Processor Module operates as the central processing unit in a PLC-5 rack, providing reliable control logic execution and communication management for all modules within the system. It continuously processes I/O data from 512 points and distributes control commands through the rack backplane to support steady state operation of all connected monitors and modules. Seamless communication is standard with the 1785-LT3, and using the DH+ Channel enables seamless data exchange with higher-level computers and other processors in the event of complex network requirements. The 1785-LT3 has made improvements in several areas over previous processor designs in addition to incorporating remote I/O adapter capability within the PLC-5 rack.
The 1785-LT3 provides essential processing functions common to the entire rack, and is a critical component of the control path, directly affecting the proper, normal operation of the overall automation system. One 1785-LT3 processor module is required per rack depending on the desired control complexity. The 1785-LT3 occupies a dedicated slot in the rack and is always positioned to manage the primary control functions.
For Remote I/O applications, the 1785-LT3 Processor Module requires connection to the Remote I/O Channel (Adapter Only) to interface with distributed field devices. In addition to standard local I/O operation, the remote configuration also performs automatic scanning. The 1785-LT3 remote I/O configuration executes communication using the 57.6 kbps transmission rate specified in the module specifications. Using this method, the remote I/O system continually monitors the status of all connected stations. If the system detects that a remote station is no longer providing valid data (outside configured response/tolerance levels), it will automatically flag the condition and place an event in the system diagnostic list.
The 1785-LT3 Allen-Bradley Processor Module may still be available for purchase and support from Apter Power beyond End-Of-Life (EOL) by the manufacturer (OEM).
Allen-Bradley 1785-LT3 Processor Module Manuals,Datasheets,Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
Allen-Bradley 1785-LT3 Processor Module Specs
General
- Manufacturer Allen-Bradley
- Model 1785-LT3
- Condition New Original ready stock
- Product Family 1785-LT,1785-LT2,1785-LT4
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
- Legacy System Maintenance: Replaces faulty modules to minimize downtime in factories running vintage Rockwell Automation PLC-5 control systems.
- Machine Automation: Controls synchronized assembly lines, pneumatic sequencing, and packaging hardware with an average execution speed of 8 ms per 1,000 words.
- Remote I/O Network Expansion: Interfaces with up to 4 I/O racks and 32 universal remote chassis over a 57.6 kbps transmission line.
- Memory Optimization: Executes repetitive logic structures and plant subroutines via Jump-to-Subroutine (JSR) commands to maximize the 6K internal memory capacity.
- Peer-to-Peer Communication: Connects multiple classic processors over a Data Highway Plus (DH+) daisy chain to share plant metrics or link central programming terminals.
- CSA Certification: Approved by the Canadian Standards Association for operational safety in industrial control deployments.
- Class I, Division 2: Rated for deployment in hazardous environments categorized across Groups A, B, C, and D explosive atmospheres.
- EN 61131-2 Standard: Meets European compliance criteria for programmable controller safety, environmental resistance, and electrical parameters.
- EMC Directive Compliance: Conforms to industrial electromagnetic compatibility limits for emissions and electrostatic/RF immunity.
- Physical PROM Upgrades: Classic Series A hardware stores operational software on chipsets. Physical updates require replacing the internal socketed communication plug PROMs (such as chip U7 or U31) rather than using modern desktop software utilities.
- Software Verification: Open the system configuration inside RSLogix 5 software, go online, and open Controller Properties to check the active firmware revision without opening the chassis.
- Legacy Tool Requirements: System-based updates require the vintage 1785 PLC-5 Programmable Controller Flash Tool suite instead of standard modern ControlFlash software.