Table Of Contents

Open and Verify Variable Connection (G Dataflow)

Version:
    Last Modified: March 15, 2017

    Opens a connection to a PSP variable and verifies that the connection opened successfully.

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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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    buffer size in elements

    The number of elements to include in the client-side buffer for the variable connection.

    If you wire a value of 2 or greater to this input, the node creates a read buffer, a write buffer, or both, depending on the read and write access settings you specify using the access input. If you wire a 0 to this input, the node uses the access input value you specify without buffering. If you wire a value of 1 to this input, the node returns an error.

    Default: 0—Specifies no buffering

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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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    timeout ms

    Time, in milliseconds, that the node waits before timing out. The operation aborts if it does not complete within timeout ms. To disable timeouts, set timeout ms to -1.

    Default: 0

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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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