A HMI connects four PLC with the same parameters (19200, N, 8, 2) through COM2 port RTU485. Because it is one-to-many, I use for loop to traverse four PLC to read variables. You only need to set the station number.
by monitoring a second variable inside each PLC, it is found that the data obtained does not change in seconds and is unstable until 2s or 3s.
is there something wrong with my way of thinking?
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