< Back to News & Events

Allen-Bradley PLC-5 Migration

December 12, 2016

In June 2017, the Allen-Bradley PLC-5 platform will be discontinued. Historically, it was one of the first platforms that could be programmed by a personal computer. Introduced in 1986, the PLC-5 was a game changer within many industries. Its popularity and use is undisputed with as many as 450,000 platforms installed throughout the world.  As the PLC-5 is phased out, use of the ControlLogix platform is on the rise.



While the migration from PLC-5 to ControlLogix has been announced, businesses have been somewhat slow to respond. Many in the industry are theorizing that response has lagged for several reasons. The PLC-5 has been a mainstay for Rockwell Automation for 30 years. During its life span, Rockwell continued to improve and modernize the platform’s capabilities, thereby allowing an automated control system to be operated with up-to-date offerings. Another reason response is slow is based on the solid design and low failure rate of the PLC-5. Many businesses consider these attributes and adapt an “if it’s not broke, don’t fix it” attitude.

Response time aside, there are many benefits to migration:

  • Support – There are more engineers in the industry that understand the ControlLogix system versus PLC-5.
  • Hardware – When the PLC-5 is discontinued, it will become difficult to find replacement hardware.
  • Obsolescence– The PLC-5 is at the end of its lifecycle. Currently, features and enhancements are only being made to the ControlLogix platform.


The actual migration or modernization process consists of integrating discontinued PLC-5 hardware with new ControlLogix hardware. To convert remote racks of IO, the existing remote IO communications network needs to be reviewed and is typically converted to Ethernet. Migration can also occur on a phased timeline. Remote IO racks can run with the new ControlLogix processor and be updated on a timeline. The PLC-5 program is also converted using the Studio 5000 programming software. Not every PLC-5 instruction has an equivalent in the ControlLogix world.  Before migration any SCADA’s, HMI’s, DCI’s,  and other programs that communicated with the PLC-5 need to be reviewed and modified to ensure that the new controller is capable of executing the code with exactness.

Companies should consider the following before beginning any migration project:

  • Overall plan – Start with an end goal in mind. How many systems need to migrate? What systems will be impacted during the migration period?
  • Downtime – How long can you afford to be down during the migration?
  • Enhancements – What do you wish your current automated control system could do for you today? How will modernizing improve operations?


caco-0307As a leading control systems integrator and electrical control panel manufacturer, Control Assemblies is beginning to reach out to our customers with PLC-5 systems about the importance of this migration. Since their inception, we have been integrating the PLC-5 and ControlLogix platforms and are industry experts in migration projects. As solutions based providers, we understand the intricacies of migration and the importance of getting it right the first time. Whenever possible, Control Assemblies works with customers to find opportunities to improve systems concurrent to any migration project. Recent customer systems improvements have included: tighter process control, additional data collection and visualization, modernized communication methods, safety systems, and redundancy.

To learn more about the platform migration process we invite you to contact a Control Assemblies Sales Representative.