Modbus TCP/IP maximun read size.



  • Hello,
    I am developing an application that uses modbus tcp/ip. I only use holding registers. I write 10 registers and I want to read 110 registers. The maximum information packet for standard modbus is 128 word. I am using the modbus slave/master of Qt 5.7 and I only can read 62 registers with an higher number I get error.

    The number of registers that I want read has been changed in slave and master. I am using readandwrite request and I also have tried readrequest with the same result.

    Is it a internal restriction? Can I change this limit?

    Thanks,
    Javier



  • For more information visit:

    https://bugreports.qt.io/browse/QTBUG-54834


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