Returns a session handle used to identify the switch module in all subsequent NI-SWITCH calls and optionally sets the initial state of the session.

This VI creates a new IVI instrument driver session for the switch module specified in the resource name. If multiple topologies are valid for that device, NI-SWITCH uses the default topology specified in MAX. The topology is also configurable in option string.

By default, the switch module is reset to a known state.

Enable simulation in option string.

An error is returned if a session to the specified resource exists in another process. The same session is returned if this VI is called twice in the same process for the same resource with the same topology.

Related Topics


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Inputs/Outputs

  • cstr.png option string (Simulate=0,RangeCheck=1,DriverSetup=topology:1127/2-Wire 32x1 Mux) —

    option string sets initial values of certain properties for the NI-SWITCH session.

    The following table lists the property string names you can use.

    Property String Name Default Value
    RangeCheck 1
    QueryInstrStatus 1
    Cache 1
    Simulate 0
    RecordCoercions 0
    DriverSetup topology:1127/2-Wire 32x1 Mux

    The format of option string is PropertyStringName=Value, where PropertyStringName is the name of the attribute shown above and Value is the value to which the property is set. To set multiple properties, separate assignments with a comma.

    If you pass an empty string option string, the NI-SWITCH session uses the default values for the properties. You can override the default values by explicitly assigning a value. You do not have to specify all of the available properties. If you do not specify an attribute, its default value is used.

    Use the Driver Setup property to set the topology or the resource type of the switch module. This attribute can contain config token/value pairs within it.

    DriverSetup=[config token]:[value];[config token 2]:[value 2]

    The following table lists valid config tokens and values.

    Token Value
    topology Refer to Devices for valid values. Default: MAX configured topology for each device.
    resourcetype daqmx for devices configured under NI-DAQmx Devices in MAX. Default: daqmx

    For example, use the following string to set an NI SCXI-1127 as a 2-wire 32x1 multiplexer configured in MAX under DAQmx Devices:

    DriverSetup=topology:1127/2-Wire 32x1 Mux;resourcetype:daqmx

    The DriverSetup string is particularly important when using NI-SWITCH through the IviSwtch class driver.

    To enable simulation, set the Simulate property equal to 1 and specify the switch module and topology of the switch module to simulate. The following string enables simulation for an NI SCXI-1127 configured as a 2-wire 32x1 multiplexer.

    Simulate=1, DriverSetup=topology:1127/2-Wire 32x1 Mux

    If the Simulate property is set to 1 and the Driver Setup property specifies a topology, the topology is used to determine which switch module to simulate. If the Driver Setup property does not specify a topology, the switch specified in resource name is simulated.

  • civrn.png resource name —

    resource name specifies the instrument resource name assigned by Measurement & Automation Explorer (MAX) (for example, PXI1Slot3). IVI logical names are also valid resource names.

  • cbool.png id query (boolean value) —

    id query is ignored.

    Because NI-SWITCH supports multiple switch modules, it always queries the switch module to determine which module is installed. For this reason, this VI may return an ID Query Failed error even if this parameter is set to VI FALSE.

  • cbool.png reset device (boolean value) —

    reset device specifies whether to reset the switch module during initialization. The default value is TRUE (1).

    Note The first call to the niSwitch Initialize With Topology VI after you reboot your computer will reset the hardware. This is the only case when the Reset flag is not honored.
    TRUE (1)

    The device will reset.
    FALSE (0)

    The device will not reset.
  • cerrcodeclst.png error in (no error) —

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

  • iivrn.png instrument handle out —

    instrument handle out identifies a particular NI-SWITCH session established with the niSwitch Initialize With Topology VI, the niSwitch Initialize With Options VI, or the niSwitch Initialize VI and used for all subsequent NI-SWITCH calls.

  • ierrcodeclst.png error out —

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