Reads values from contiguous input registers. The maximum number of input registers this VI can read is 125.


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Inputs/Outputs

  • cModbus_Masterlvclass.png Modbus master in —

    Modbus master in specifies the reference to the Modbus master instance. Use the Create Master Instance VI to create a Modbus master instance.

  • cu16.png starting address —

    starting address specifies the initial address for the read operation. Valid values are between 0 and 65,535, where 65,535 is the maximum number.

    The address that this VI reads is 0-based, meaning that the address numbering convention for the Modbus slave starts at 0.

  • cu16.png number of input registers —

    number of input registers specifies the number of input registers you want to read. Valid values are within the range [1, 125]. After you specify a value for number of input registers, check the value you specify for starting address. Ensure that you do not use this VI to read the value of an input register whose address is larger than 65,535.

    Otherwise, LabVIEW returns error code -389113.

  • 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 Modbus master out —

    Modbus master out returns a duplicate of Modbus master in.

  • i1du16.png register values —

    register values returns the input register values.

  • 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 Read Input Registers VI:

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