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  1. Qt
  2. QTBUG-77940

When a modbus device is absent or stops communication then sometimes the timeout event is not being sent

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      Description

      When a modbus device is absent or stops communication then sometimes the timeout event is not being sent. This happens in rare cases and will come up at the start of the next outgoing message.

      Here is some sample output from when it hangs after unit 193:

      NFO: ModbusScanner [ "SensorBus" / 189 ] TIMEOUT @@@ "14:49:41.060" 
      INFO: "M_READ [ Id:190 Addr:205 Len:1 ]" @@@ "14:49:41.082" 
      INFO: ModbusScanner [ "SensorBus" / 190 ] TIMEOUT @@@ "14:49:41.136" 
      INFO: "M_READ [ Id:191 Addr:205 Len:1 ]" @@@ "14:49:41.158" 
      INFO: ModbusScanner [ "SensorBus" / 191 ] TIMEOUT @@@ "14:49:41.211" 
      INFO: "M_READ [ Id:192 Addr:205 Len:1 ]" @@@ "14:49:41.233" 
      INFO: ModbusScanner [ "SensorBus" / 192 ] TIMEOUT @@@ "14:49:41.287" 
      INFO: "M_READ [ Id:193 Addr:205 Len:1 ]" @@@ "14:49:41.309" 
      INFO: "M_READ [ Id:194 Addr:205 Len:1 ]" @@@ "14:49:41.384" 
      INFO: ModbusScanner [ "SensorBus" / 193 ] TIMEOUT @@@ "14:49:41.384" 
      INFO: ModbusScanner [ "SensorBus" / 194 ] TIMEOUT @@@ "14:49:41.437" 
      INFO: "M_READ [ Id:195 Addr:205 Len:1 ]" @@@ "14:49:41.459" 
      INFO: ModbusScanner [ "SensorBus" / 195 ] TIMEOUT @@@ "14:49:41.513" 
      INFO: "M_READ [ Id:196 Addr:205 Len:1 ]" @@@ "14:49:41.534" 
      INFO: ModbusScanner [ "SensorBus" / 196 ] TIMEOUT @@@ "14:49:41.587" 
      INFO: "M_READ [ Id:197 Addr:205 Len:1 ]" @@@ "14:49:41.610"
      

      Some other information:

      • Frame sent by master does not contain any data
      • Checksum seems to be wrong
      • The physical layer and what is in the application output does not seem to match

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            Assignee:
            heimrich Karsten Heimrich
            Reporter:
            andysh Andy Shaw
            Votes:
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              Dates

              Created:
              Updated:
              Resolved:

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