Hi everyone, I’ve been researching on topics related to this question: Modbus problem ReadHoldingRegisterRequest Modbus TCP disconnection and no reconnection [SOLVED] Troubleshoot Modbus RTU device connection Modbus RTU over TCP Timeout Issue Server keeps dropping modbus connections to all plc…

If you have another Modbus client (Simply Modbus, modpoll, etc…) that can successfully communicate then it often helps to compare Wireshark captures and spot the difference.

Modbus TCP dropping connections

Ignition

Gomez August 6, 2025, 7:16am 14

Hi, try to check the OMB_Time or set al least 1 variable with a lower scanclass than 1 second ( ie. 250 ms )