Writes the data from write buffer to the device or interface specified by VISA resource name.


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Inputs/Outputs

  • cvsrn.png VISA resource name —

    VISA resource name specifies the resource to be opened. The VISA resource name control also specifies the session and class.

  • cstr.png write buffer —

    write buffer contains the data to be written to the device.

  • cerrcodeclst.png error in (no error) —

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

  • ivsrn.png VISA resource name out —

    VISA resource name out is a copy of the VISA resource name that VISA functions return.

  • iu32.png return count —

    return count contains the actual number of bytes written.

  • ierrcodeclst.png error out —

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

    • Whether the data is transferred synchronously or asynchronously is platform-dependent. Right-click the node and select Synchronous I/O Mode»Synchronous from the shortcut menu to write data synchronously.

    When you transfer data from or to a hardware driver synchronously, the calling thread is locked for the duration of the data transfer. Depending on the speed of the transfer, this can hinder other processes that require the calling thread. However, if an application requires that the data transfer as quickly as possible, performing the operation synchronously dedicates the calling thread exclusively to this operation.

    Note In most applications, synchronous calls are slightly faster when you are communicating with four or fewer instruments. Asynchronous operations result in a significantly faster application when you are communicating with five or more instruments. The LabVIEW default is asynchronous I/O.

    Examples

    Refer to the following example files included with LabVIEW.

    • labview\examples\Instrument IO\Serial\Serial.lvproj
    • labview\examples\Instrument IO\GPIB\GPIB with VISA functions.vi