Hi, I saw that the subject was already discussed but, I can't find the way to connect and the suitable library for Modbus communication with a PLC thru RS485. Can anyone help me? Thanx alot!
I found lots of wiring diagrams here:
http://images.lmgtfy.com/?q=Arduino+MAX485
I found a bunch of Arduino Modbus examples here:
http://lmgtfy.com/?q=Arduino+Modbus
I guess the Plc is going to be slave, then you need to program arduino as a master with modbus master library (google it there are a lot).