Creates a serial or TCP Modbus master instance. You must manually select the polymorphic instance to use.

You can use the Modbus master instance to perform read and write operations on Modbus slaves. The default read and write operation timeout is 5,000 ms. You can use the Property Node or the Set Timeouts VI to change the timeout.

Use the pull-down menu to select an instance of this VI.


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Inputs/Outputs

  • cstr.png address —

    address specifies the TCP/IP address of the Modbus slave with which you want to communicate.

  • cu16.png port (502) —

    port specifies the TCP port of the Modbus slave with which you want to communicate. The Modbus slave can be a Modbus slave you create or a third-party Modbus slave. If you want to communicate with a third-party Modbus slave, check the documentation for the Modbus slave to find its port. The default is 502.

  • cerrcodeclst.png error in (no error) —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • iModbus_Masterlvclass.png TCP master instance —

    TCP master instance returns a TCP Modbus master instance.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.

    • Examples

    Refer to the following VIs for examples of using the Create Master Instance VI:

    • labview\examples\Data Communication\Modbus\ModbusLibrary\Modbus Library.lvproj
    • labview\examples\Data Communication\Modbus\Redundant Modbus Masters\Redundant Modbus Masters.lvproj