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Open Variable Connection (G Dataflow)

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Last Modified: March 15, 2017

Opens a connection to a PSP variable.

You cannot buffer data that you read or write with this node. To enable buffering, use the Open and Verify Variable Connection or Open Variable Connection in Background node instead.

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Note  

NI recommends that you use Tag nodes instead of this node for new applications you create.

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shared variable refnum in

The reference to the PSP variable.

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data type

The data type of the PSP variable.

If you specify the data type using shared variable refnum in, this node removes the data type input. If you specify the data type upon opening the connection, this input is unavailable for subsequent read nodes.

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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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access

Read access and write access settings for the PSP variable.

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Read Access

Read access settings.

Name Description
Allowed You can use the variable connection to read the value of the PSP variable.
Required You can use the variable connection to read the value of the PSP variable. If you select this option and cannot open the variable connection for reading, the node returns an error.
None You cannot use the variable connection to read the value of the PSP variable.
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Write Access

Write access settings.

Name Description
Allowed You can use the variable connection to write to the PSP variable.
Required You can use the variable connection to write to the PSP variable. If you select this option and cannot open the variable connection for write, the node returns an error.
Denied You cannot use the variable connection to write to the PSP variable.
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shared variable refnum out

The reference to the PSP variable.

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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.

Where This Node Can Run:

Desktop OS: Windows

FPGA: This product does not support FPGA devices

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