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Get Control Value (G Dataflow)

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Last Modified: February 28, 2020

Retrieves the value of a named control or indicator as variant data.

Use Variant to Data to convert the data to another data type.

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reference in

A reference to a VI.

Use Open VI Reference or Static VI Reference to obtain a valid reference for this input.

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control name

Label for the control or indicator whose value you want.

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error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

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reference out

Unchanged reference to the same VI.

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control value

Value of the control or indicator.

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error out

Error information.

The node produces this output according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Using Get Control Value

This node requires the referenced VI to have a panel. To use this node to retrieve data from an application, make sure you include the panel when you build the application.

Verifying Valid Data Values

For optimization purposes, the application does not store data values of controls and indicators for any VI until you display the panel or call this node with a reference to the VI.

The first time you use this node to retrieve data from a referenced VI without first opening the panel, this node returns the default values of the control or indicator rather than the actual values. Thereafter, it returns the actual value.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application

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