No connection to Modbus Slave

[riso77]

Hi all,

I am having difficulty to connect to a Modbus Slave running locally (on the same machine as Wincc OA).
This is what i did:

1. Modbus slave is running locally, port 502 is opened and listening (Slave ID/Unit address set to 1)
2. Modbus driver running
3. The PLC is configured (socket of the PLC 127.0.0.1:502, Unit address = 1, PLC number = 1
4. I created a boolean DPE "coil_status" with Reference M.1.1.1 and (polling 1st Coil register on PLC 1) with Poll time = 500 ms
5. Clicking the Apply button on the "Periphery - MODBUS / UNICOS" panel brings the message in the Logviewer "Unexpected state, ModPolGroup, addItem Cannot add poll address due to error in address M.1.1.1" and the State "Not connected" persists.
6. I have tried running the Modbus slave software also on a different machine (with changing the socket of the PLC in configuration) and sniffing the traffic with wireshark, but there is no communication from Wincc OA towards the machine where the Modbus Slave is running.

is there anything I am missing in the configuration?

thank you very much for clearing. https://www.winccoa.com/fileadmin/image ... _issue.png

[Gertjan van Schijndel]

Perhaps it goes better if you also set the 'Type of transformation'.

[riso77]

definitelly, Choosing "boolean" in the field Type of transformation made the trick

thank you