Suspends execution of an application thread and waits for an event type for a time period not to exceed that specified by timeout.


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Inputs/Outputs

  • cu32.png timeout (0) —

    timeout specifies the time, in milliseconds, that the function waits for the event.

  • 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.

  • cu32.png event type (all enabled) —

    event type is the logical event identifier.

    You can select from the following VISA event types.

    Service Request0x3FFF200B
    Trigger0xBFFF200A
    Clear0x3FFF200D
    VXI Signal0x3FFF2020
    VXI/VME Interrupt0xBFFF2021
    VXI/VME Sysfail0x3FFF201D
    VXI/VME Sysreset0x3FFF201E
    GPIB CIC0x3FFF2012
    GPIB Talk0x3FFF2013
    GPIB Listen0x3FFF2014
    PXI Interrupt0x3FFF2022
    Serial Break0x3FFF2023
    Serial TermChar0x3FFF2024
    Serial CTS0x3FFF2029
    Serial DSR0x3FFF202A
    Serial DCD0x3FFF202C
    Serial RI0x3FFF202E
    Serial Character0x3FFF2035
    USB Interrupt0x3FFF2037
    All Enabled (default)0x3FFF7FFF

    Refer to the NI-VISA Help for more information about event types.

  • cvsrn.png event class (Generic Event) —

    event class specifies the class of event for which the function waits. The default is Generic Event, meaning the function recognizes any class of event.

  • 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 event type out —

    event type out identifies the event type received if the wait was successful.

  • ivsrn.png event —

    event is valid if the wait was successful.

    Wire event to a Property Node to get further information about the event. Wire event to the VISA Close function when examination of the event is complete.
  • ierrcodeclst.png error out —

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

    • You can set this function to perform I/O operations synchronously or asynchronously. By default, the function handles I/O operations asynchronously. Right-click the function and select Synchronous I/O Mode»Synchronous from the shortcut menu to synchronously wait for an occurrence of the specified event.

    Note In most applications, synchronous calls are slightly faster when you are communicating with 4 or fewer instruments. Asynchronous operations result in a significantly faster application when you are communicating with 5 or more instruments. The LabVIEW default is asynchronous I/O.

    Refer to individual event descriptions for context definitions. If the specified event type is All Events (0x3FFF7FFF), the operation waits for any event that is enabled for the given session.

    Note You must call the VISA Enable Event function for a given session before using the VISA Wait on Event function.

    If a session's event queue becomes full and a new event arrives, the new event is discarded. The default event queue size per session is 50. If you expect more than 50 unhandled events to arrive, you can use the General Settings:Maximum Queue Length property to set event queue size programmatically.

    Examples

    Refer to the following example files included with LabVIEW.

    • labview\examples\Instrument IO\Serial\Detect Serial Break Event.vi