master

[clau]

I am working with the modbus/ rtu protocol for communicate one PC, one Magelis, one PLC (TWIDo modular ), and one PM500. I want to do a SCADA so, the PC is going to be the master, i can do that or the Magelis must be the master??. I need other port RS485?

[support]

We are not sure about the "Magelis". The PC will need to be a master if you are using SCADA. The PLC will be a slave. If "Magelis" need to be a master it can be connected to the PLC's RS485 port using an Auto485 adapter. Since the PLC's two ports are totally independent and can process MODBUS protocols from two masters simultaneously it is not a problem if this is what you need.

Note that the PLC may also be a MODBUS slave on one serial port and become a MODBUS master on the other serial port at the same time! This flexibility should gives you the ability to configure your system in the most suitable way.