Hi @itsmomito,
My colleague reminded me of another method that may be more efficient. This method involves setting up one Codesys PLC as a Modbus server, while the other acts as a Modbus client. When you have time, please download and review the “CODESYS Modbus Server Demo” within the demo projects section of our forum: Link
After setting up the parent PLC as a Modbus server, you can use the “Modbus_TCP_Slave” device within your child PLC’s application to read the remote PLC:
The process of adding the “Modbus_TCP_Slave” device is explained within this post: Link