Case Studies

Allen-Bradley PLC-5 to ControlLogix Migration

Posted in Allen Bradley PLC, Chemical, HMI and SCADA, Manufacturing Automation and Intelligence, PLC Programming


DMC has completed software and hardware migrations from obsolete Allen-Bradley PLC-5 to ControlLogix by specifying hardware, developing commissioning plans, and migrating and commissioning the modern software for a customer in the chemical manufacturing industry.


DMC has headed migration projects on behalf of the customer to migrate chemical extrusion processes running with PLC-5 Controllers, 1771 remote IO, and Flex I/O on Data Highway Plus (DH+) communication protocol. 

end product
Client's End Product

The client engaged DMC to specify similar modern control hardware and develop changeover plans to minimize downtime during commissioning.  DMC worked with Allen-Bradley distributors and the client’s electrical contractor to determine which control parts had a direct upgrade and which electrical components would be best re-wired for future maintainability.

DMC utilized Allen-Bradley’s PLC-5 to ControlLogix software migration tool to create functionally equivalent PLC programming for the ControlLogix platform.  Since this customer had little controls documentation available to them, DMC worked with the customer to verify expected functionality and to specifically verify high-risk portions of the code such as interlocks that could cause equipment damage or product mixing if not working correctly. 

DMC also migrated the tag and communication paths of the client’s Wonderware InTouch system and reconfigured the HMI system, a terminal server-client layout utilizing ACP ThinManager.

During commissioning, DMC worked with the client’s contractors directly to check out and troubleshoot new hardware. DMC’s engineers provided support to the client’s operations and process engineering teams to start up equipment and implement adjustments during production.  DMC developed a close relationship with the customer and provided a high-level control system understanding to identify and improve portions of the original code function. 

DMC provides ongoing support and training for the client personnel on an as-requested basis.

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Customer Benefits

  • Long-term maintainability of control hardware
  • Reduced downtime
  • Increased diagnostic capability
  • Incremental specification, development, and commissioning of hardware and software migration from obsolete Allen-Bradley PLC-5’s to ControlLogix PLCs.
  • Ability to quickly improve control software and implementation through the use of modern ControlLogix platform capabilities and tools
  • Ability to easily expand system through additional remote IO


  • ControlLogix PLCs
  • Flex I/O
  • Data Highway Plus (DH+) to Ethernet/IP communication protocol upgrade
  • I/O Wiring Conversion System, PLC-5 1771 to ControlLogix 1756
  • PLC-5 to ControlLogix Migration Tool
  • Wonderware InTouch Modern Applications
  • ACP Thinmanger