niSwitch Initialize With Options VI

NI Switches Help

Edition Date: April 2015

Part Number: 375472H-01

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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

niSwitch Initialize With Options

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resource name specifies the resource name of the switch module to initialize. IVI logical names are also valid resource names.

Syntax:

Optional fields are shown in square brackets ([]). The default values for optional fields are as follows:

chassis ID = 1

bus number = 0

Configured in MAX Under Valid Syntax
Devices and Interfaces DeviceName
Traditional NI-DAQ (Legacy) Devices SCXI[chassis ID]::slot number
PXI System PXI[bus number]::device number

The following table lists example resource names.

Resource Name Description
SC1Mod3 NI-DAQmx module in chassis SC1 Slot 3
MySwitch NI-DAQmx module renamed to MySwitch
SCXI1::3 Traditional NI-DAQ (Legacy) module in chassis 1, Slot 3
SCXI::3 Traditional NI-DAQ (Legacy) module in chassis 1, Slot 3
PXI0::16 PXI bus 0, device number 16
PXI::16 PXI bus 0, device number 16
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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.

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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.

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

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status is TRUE (X) if an error occurred before this VI ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI ran. The default is FALSE.

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code is the error or warning code. The default is 0. If status is TRUE, code is a non-zero error code. If status is FALSE, code is 0 or a warning code.

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source describes the origin of the error or warning and is, in most cases, the name of the VI that produced the error or warning. The default is an empty string.

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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 (DAQmx or Traditional DAQ) 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 or legacy for devices configured under Traditional NI-DAQ (Legacy) 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.

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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.

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

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status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.

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code is the error or warning code. If status is TRUE, code is a non-zero error code. If status is FALSE, code is 0 or a warning code.

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source describes the origin of the error or warning and is, in most cases, the name of the VI that produced the error or warning.

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