European Machine Builder

PLC Migration for a Packaging Machine

A legacy controller at end of life on a machine still in daily production. Hardware migrated, program restructured and the HMI rebuilt — with the changeover kept inside one weekend.

Challenge

The machine ran on a controller that was no longer available and no longer supported. Spare parts were being bought second-hand, the original program had no documentation, and the customer could not risk an extended stoppage on a machine that was still in daily production.

Solution

PLC hardware migration to a current platform, combined with a restructure of the program rather than a like-for-like conversion, and a rebuild of the HMI screens on the new operator panel. The new program was built and tested offline against a simulated I/O set before any hardware was touched.

Result

Commissioning time on site was reduced to a single weekend shutdown. The machine is now on a supported platform with a documented program, and the customer's own maintenance team can make changes without calling anybody.

Engineering Work

PLC Programming
Program Restructuring
HMI Programming
I/O Testing
Remote Commissioning

The conversion tools available for this kind of migration will produce something that compiles. They will not produce something anybody wants to maintain — addressing is carried over literally, structure is lost, and the result is harder to read than the original.

We took the alternative route: use the old program as the specification, and write a new one. That takes longer up front and it is the reason the on-site window was short.

Offline testing mattered more than anything else here. With the new program exercised against simulated inputs before the shutdown, the weekend was spent on wiring and verification rather than on discovering logic problems with production waiting.