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  1. Qt
  2. QTBUG-103609

Multiple Modbus PDUs in single TCP frame

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Details

    • Bug
    • Resolution: Unresolved
    • P1: Critical
    • None
    • 5.12.5
    • SerialBus: MOD Bus
    • None
    • Linux/Yocto

    Description

      QModbus Client sometimes sends Modbus/TCP frame, which includes multiple Modbus PDUs.​
      According to the Modbus implementation guide, it's advised against sending multiple MODBUS requests or responses on the same TCP PDU.​
      In the attached Wireshark log, QModbus client (192.168.1.2) sends two Modbus PDUs in one TCP segment.​
      Timeout: 50 msec​
      Number of retry : 3

      Attachments

        1. 0517_NG.pcapng
          1.01 MB
        2. ModbusMasterTest.zip
          3 kB
        3. ModbusSlave.zip
          2 kB
        4. wireshark_two_modbus_pdus.png
          wireshark_two_modbus_pdus.png
          161 kB
        For Gerrit Dashboard: QTBUG-103609
        # Subject Branch Project Status CR V
        415279,1 Immediatly flush the socket after a write dev qt/qtserialbus Status: NEW 0 0

        Activity

          People

            heimrich Karsten Heimrich
            yoshimiz Yoshiyuki Shimizu
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            Dates

              Created:
              Updated:

              Gerrit Reviews

                There is 1 open Gerrit change