I have 2 hot-swappable ABB PM573 ETH PLC.
Using the Modbus TCP/IP protocol I have to send data to a third-party controller. Modbus programming completed and register addresses assigned.
But I am facing a big issue that is, When I am polling the data with MODSCAN or Modbus poll, after 1 valid poll and response the Modbus communication terminates.
Can anyone help me to resolve this problem?
(I am new to ABB Platform)

 

ModScan will open a Modbus/TCP connection and keep it open while making requests (it does not close the connection after each request/response). Therefore, it sounds like the ABB is closing the connection prematurely. You may need to change your Modbus TCP/IP Server Settings on the ABB. Take a look at this forum post:
https://www.plctalk.net/threads/abb-plc573-eth-n-w-drop.101811/

 

if there is no communication and socket is idle , the ABB server closes the connection. you can send keepalive message when socket is idle to avoid this problem