Thanks for your quick feedback! We are planning to replace the raspi with the IPC (Carbon 300 compact rugged industrial PC). We only use opc-ua as a protocol. Node red fetches the data and transforms it for the DB. So at the moment we are using OPC-UA as a node in node red. The PLC (Simatic ET 200SP) reads process values from the brewery. The challenge here is that it is already installed and difficult to access. To connect the Modbus to the PLC, a Modbus communication interface would be required, so to reduce the load on the PLC and remain flexible, we decided to use a Modbus gateway. But we are also open to adapt our plan.