Yes. I wrote some PG3 code with the PLC as Modbus (RTU) master supporting the functions 01 (read coil), 03 (read holding register), 15 (force multiple coils) and 16 (Preset multiple register.
Besides using Modbus, there are some questions
- is the SAIA PLC going to the master or slave?
- is it Modbus ASCII or RTU ?
- which functions to use?