Dear all

I have S7-1200 as Modbus RTU master. I have read the value from a slave but when the Slave restart or power off then on, S7-1200 can not connect to the slave

Would you please show me how to set automatic connect again after connection lost. I see on "MB_COMM_LOAD_DB" has RESP_TO to retry connection. Is it true  ?
 

Hello,

yes, if Slave not respond to that Timeout value end (standarad 1000 ms), Master repeat request to Slave. As Help show:

Response timeout:

Time in milliseconds allowed by "MB_MASTER" for the slave to respond. If the slave does not respond in this time, "MB_MASTER" repeats the request or terminates the request with an error if the specified number of retries has been sent.
5 ms to 65535 ms (default = 1000 ms).

In my experience it works ok, simply Master repeat request every 1s until Slave not respond to request. You can also simulate this with some PC application as Slave, this is better preparing code functionality, then test on real device.