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Need help for Modbus TCP beetwen RPI and PLC

groy
2018-02-10
2018-02-11
  • groy - 2018-02-10

    Hi everyone,
    I try to use Modbus TCP beetwen RPI and PLC and I also make init with "Modbus Slave Init" and the value was transfered to PLC. I try read holding register at 0x0000 and all status in codesys "device" is ok but why my value is always zero even though I change the value. I used another tool as Modbus TCP master but the value is good, could anyone help me for this problem?

    Regards
    Roy

    IMG: MB_RPI.jpg

     
  • eschwellinger

    eschwellinger - 2018-02-10

    Hi,
    You need to call the mapped variables somewhere in the Pou's if not called tge values will not updated.
    BR
    Edwin

     
  • groy - 2018-02-11

    Hi Edwin,

    Thank you for your explanation, I don't know if it must process in Pou

    Roy

     

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