Communication using Modbus RTU between two AC500-eco PM554 PLCs.
I am trying to communicate two AC500-eco PLCs via Modbus RTU. I am connecting them with the TK682 cable. In Automation Builder the configuration of the interfaces for both PLCs have been done in COM 2 > (Modbus). I´ve established one of them in operation mode Client (Master) with address 0 and the other one as a Server (Slave) with address 2.
As far as I´ve researched, everything with the Modbus addressing is fine. In the master program, using the FB COM_MOD_MAST , I am starting to write from %MW0.500 register just sending a bool encapsulated in a word but I´m not receiving anything in the Slave.
In addition I'm getting ERRNO 8211 which error description is: Timeout
COM_MOD_MAST: Slave did not respond within the specified time
HA..: No Ethernet link
Can someone please give me an example of how to communicate these two using Modbus RTU?
Voted best answer
According to your pictures you have configured COM2 Port, and you used TK682 cable. As far as I know that cable is used for between AC500eco PLCs COM1 port and CP600 panels only.
For Com2 port you have to prepare your own wirings:
You can use above picture for details.
For slave side you have to create your variable in Global Variable section, not directly in PLC_PRG POU.
Hope it helps you.
- Two configurations: 1 PLC as Master with address 0 and the other PLC as Slave with address 2.
- PB1 is a digital input configured in the Master PLC.
- OUT1 is a digital output configured in the Slave PLC.
Thanks in advance,