CODESYS Modbus TCP Master/Slave - BK9000 - doesn't work

  • Dude82

    Dude82 - 2019-08-27

    In CODESYS 3.5 V15 I try to read data on Modbus from a Beckhoff Ethernet coupler ( BK9000+KL3314: input for thermocouple + KL3064 : Input 0-10V)
    I have added an Ethernet Generic device and then add Modbus TCP Master and Slave (as I have seen in others threads).
    I think I have put the proper parameters (IP adress: = my BK9000 on the network, port = 502)
    I have added input canal Chanel 1 with Read Holdings register (Offset = 1 (=0x0001) and data = 1) but I can't get any value when the program runs on the PLC (here a Raspberry with Jessie)

    This is very surprising to me , because I can read both the value usine Python (with the pymodbus lib)
    in python 3.7.4 on my windows computer

    from pymodbus.client.sync import ModbusTcpClient
    client = ModbusTcpClient('', '502')
    print('input: ', rr.getRegister(0))
    It gives me the proper value of the Thermocouple

    When I use KS2000 from Beckhoff, I can read also the value from Channel 1.

    Do you know what i'm doing wrong in CODESYS ? It makes me made not to understand where the problem is.

    IMG: Data_read_on_KS2000.png

    IMG: Config_Modbus_Slave_device.png

    IMG: Config_Ethernet_device.png

  • Dude82

    Dude82 - 2019-08-27

    Solution found.
    Sometimes I feel that I'm not very clever. By the way, I just forgot to enabled an option about the updated of the variable.
    indeed in the configuration of the PLC device (Here a Raspberry): Enable 1 ("Use bus cycle task if not used in any task") must be used in my project.

    I can now get the thermocouple values through MODBUS.

    IMG: problem_soved.jpg

    IMG: option_to_solve_the_problem.jpg


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