A controls engineer was reviewing an obsolescence notice for a DCS when he asked me a question I hear more often now: “If we move to an open architecture, why should we throw away the programming model our engineers already know?”
We shouldn’t. The plant had control applications refined over years, operators trusted them, and the engineering team knew how to maintain them.
Yet the proposed migration budget ran into millions because moving to supported infrastructure meant converting applications, rebuilding configurations, retesting interfaces and proving that the new system behaved like the one it replaced.
Millions of dollars to get back to where the plant already was.
IEC 61131 was not creating that cost. The dependency between the application and the supplier’s execution environment was.
Industry has spent decades building applications, libraries, engineering practices and workforce skills around IEC 61131. There is real value in those applications: process knowledge, operating experience and engineering decisions built up over years of running the plant. Recreating that value every time the platform changes is a poor use of engineering time.
This is why I believe Open IEC 61131 is the practical direction for industrial control. O-PAS provides a path for IEC 61131 applications to be deployed, managed and made more portable across open runtimes, reducing the dependency between the control application and the infrastructure underneath it.
A useful portability test is simple. Pick one important IEC 61131 application and ask your engineering team what would actually be required to run it somewhere else. Document the logic, libraries, configuration, engineering tools, interfaces, validation work and supplier involvement that would have to change.
If most of that list belongs to the platform rather than the process, you have found where future migration cost is building up.
The better outcome is straightforward. A compute platform reaches end of support. The controls engineer moves the existing application to a supported environment, runs the required validation, signs off the record and returns it to service. The project scope is based on proving that a valuable application still works, rather than paying an engineering team to recreate it.
Hardware can follow a hardware lifecycle. Infrastructure can follow an infrastructure lifecycle. The control application can follow the process it was built to control.
Industry already knows IEC 61131. The opportunity is to preserve that investment while opening the environment around it.
If you are evaluating application portability or an O-PAS modernisation strategy, start with one existing control application and run the portability test above. The OPA Community Beginner’s Guide at opacommunity.com provides vendor-neutral background on O-PAS architecture before those requirements reach the procurement specification.
For your most important IEC 61131 applications, where would the larger migration cost sit today: the application logic, the vendor-specific libraries and tools, or the validation required to move it?
Send me one of the three through the Contact page and I’ll tell you which part of the architecture I would examine first.