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The time has come to migrate from Allen Bradley PLC-5 to ControlLogix

Jun 14, 2018 4:58:54 PM

In June  of 2017, the PLC-5 Control System was discontinued by Rockwell Automation and is no longer available or supported. Although the PLC-5 has been a very robust piece of hardware, its life is limited and there are lots of systems currently in use that run the risk of failure without a reduced-downtime replacement.  Since Rockwell is no longer supplying replacement parts for these systems, many users are looking to eBay for replacement parts that are often very expensive and have no guaranty.

Rockwell is encouraging customers to migrate from the PLC-5 Control System to the ControlLogix PLC platform, for which, hardware component and support is readily available.  That said, an automation system upgrade from a PLC-5 to ControlLogix can be far more challenging than just installing new hardware. The ControlLogix (CLX) series is faster and easier to integrate with MES and ERP systems. Up-to-date hardware is accompanied by current software sets, making the ControlLogix platform simpler to diagnose with straightforward communications protocols.  This new hardware also supports an expansive range of I/O and communication modules that allow them to be adapted to virtually any application.

Syscon is a Recognized Rockwell Partner                    PLC-5 pic 

Path Forward

The easiest way to make the transition is with a conversion kit made to link the new hardware to the existing wiring, minimizing down-time. Since this is generally a one-size-fits-all solution, manufacturers need to realize that replacement of hardware can lead to serious problems with functionality if not executed correctly.

Syscon Automation recommends that manufacturers consult a control systems integrator about a custom solution based on your facilities unique requirements.  There are several advantages to this approach including less downtime due to equipment failure, assured quality parts and the cost savings realized by the labor hours saved by trusting an expert control systems integrator who can deliver increased up-time.

We recommend beginning with a life-cycle analysis of the current production equipment and spares inventory. A thorough review of this information will help to prioritize the modernization needs and goals. It is important to work with an experienced team who is prepared to provide on-site assessments, migration planning services, start-up and commissioning of the modernized control architecture. From project management to start-up, it is important to define and implement an effective modernization strategy for your facility that goes beyond simply addressing your legacy equipment to truly optimizing your operation.

When you’re ready to do the actual upgrade, you have the option of replacing the old PLC-5 entirely or it can be approached as a phased migration where the processor and HMI are upgraded first, then the remote I/O racks in the rest of the plant. That phased approach has the quick recovery advantage of easily switching between the old and new processor and HMI hardware. Once the new hardware is mounted, powered, and programmed (in isolation from the process), the I/O can be moved to it in just a few minutes, allowing for a trial run of the new system. If it is successful, production can recommence on the new processor and HMI. If not, the old PLC-5 processor and HMI can be put back into service in just a few minutes, and the problem sections of the new configuration addressed and simulated again before the next conversion attempt.

There are generally a few recognized phases to a conversion process that include:

Phase 1 – Application Code Conversion

There are several benefits to this part of the process including testing the application code before implementation, converting 80-100% of code using automated code conversion, and taking advantage of powerful constructs and features (like structures and integrated motion) that can be leveraged to improve the application.

Phase 2 – Replace PLC-5 Controllers

During this phase, it’s important to maintain the existing field wiring to minimize the commissioning time and effort.

Phase 3 – HMI/EOI Migration

At this point in the process, more than 80% of the time, we find that no further modification is required.  A Utility will generate a conversion log that identifies features not supported by the new hardware selected. At that point, manufacturers have the option to take advantage of enhanced features and graphics and to implement changes that allow for a better integration with controllers.

Phase 4 – I/O Replacement

During this phase, it’s extremely important pay attention to the details.  For example, you’ll want to make every effort to maintain existing field wiring, minimize commissioning time, cross reference documentation to assure correct I/O selection and update the historical back-up for future troubleshooting and/or diagnostics. The I/O structure changes you make may allow for an upgrade to Ethernet.  A ControlLogix (CLX) RIO module is needed to maintain communication to 1771 I/O temporarily during a planned I/O cutover. Eventually, this will be migrated over to an Ethernet-based CongtrolLogix I/O.  Again, a qualified control systems integrator can help you determine if the time is right and if the associated cost fits your budget.

Contact Syscon Automation today, our experienced team will implement a tried and tested phased approach to your migration project by deploying our custom code conversion tools to quickly create new code and reduce errors.  Bottom line, Syscon Automation has the chops to speed up migration while reducing production down time and providing you with the peace of mind that your PLC-5 upgrade project will be done right.

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Jon Grimes

Written by Jon Grimes