Engineers have developed a solution to replace obsolete B&R controllers in car wash facilities without replacing existing hardware or rewriting automation projects. The system uses mini-PCs running the ARsim runtime environment, which handles logic and visualization while communicating with legacy B&R X20 modules via a custom gateway.
The gateway bridges the POWERLINK protocol, used by the original B&R racks, to Modbus TCP. This setup allows the system to maintain a 2-millisecond cycle time for critical tasks like flow meter pulse counting and chemical dosing, which are processed on a dedicated CPU core isolated using Ubuntu with a PREEMPT_RT patched kernel.
The team created a custom driver for Intel I226-V network cards by porting and patching the openPOWERLINK stack, which lacked support for modern hardware and recent Linux kernels. The deployment process is fully automated via scripts, ensuring the system can operate autonomously without internet access.
To manage system stability, the solution employs cgroups to prevent the ARsim runtime from interfering with the real-time core. Additional watchdog services monitor the status of the simulator and the gateway, automatically restarting processes if they fail to ensure continuous operation of the car wash equipment.
