Modbus tcp - channel

jens
2024-06-13
2024-06-13
  • jens - 2024-06-13

    Help wanted

    This is the first time i'm doing a Modbus Tcp project.
    I have some VLT with a extension module MCA-122.
    i'm currently unable to write to the VLT slave, but i can read from status word parameter=1603 and address := 16029 where the address is calculated from parameter is ((id x 10)-1).

    in the manual the functions that are supported are 3 hex, 6 hex, 10 hex, b hex and 11 hex.
    read holdin registers, write single register, write multiple registers, get comm. event counter, report slave id.

    • i'm only using the Modbus Slave Channel is this wrong when trying to write to the vlt ?
     
  • gatto

    gatto - 2024-06-13

    Hi can you give more details?
    Are you talking about a danfoss? wich model?
    Can post the configuration of channel'

    I used, on the past, serial modbus with danfoss fc280
    I remember ((id x 10)-1)
    I remember that you couldn't use continuous reading/writing of the directors but you had to use them one at a time.
    it seemed that reading empty registers (caused by x10) was not accepted by danfoss.
    So I had created a scan that used just one register, then the next etc etc with a timed interval.
    But this was for the serial, I don't know if it's the same thing with ethernet.
    I currently use Ethernet TCP/IP interface with FC280.

     

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