This is a short announcement of an updated version of the open source PLC emulator.

Performance issues have been identified thanks to Patrick Rogge and his comments to the How to setup and run PLC emulator for SAP EWM MFS blog.

Patrick has noticed unusually high CPU usage by essentially idle emulator instance. The issue has been noted in the project’s GitHub repository – High CPU utilization running the SIM on Windows

The root cause of high CPU usage were busy waiting threads.

I have revised the emulator approach to concurrency handling and reimplemented affected classes. Now the CPU usage by idle threads is negligible.

The new version of the emulator is made available in the master branch of the GitHub repository. Also the updated jar file is provided – mfsplc.jar.

Let me know how the updated version works for you and feel free to provide any questions, remarks, bugs or feature requests with GitHub issues of the project.

Make sure to check out other blogs about the emulator.