IMAQ Extract Buffer VI

NI-IMAQ VI

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IMAQ Extract Buffer VI

Installed With: NI Vision Acquisition Software

Extracts a buffer from a continuous acquisition. IMAQ Extract Buffer allows for the examination of the buffer during acquisition. The buffer is extracted from the acquisition and protected from being overwritten until IMAQ Extract Buffer is called again. When IMAQ Extract Buffer is called, any currently extracted buffer is reinserted into the buffer list.

If the buffer remains extracted long enough that the acquisition hardware wraps around the buffer list and encounters the extracted buffer again, the acquisition will stall, increment the lost frame count, and the extracted buffer will not be overwritten.

IMAQ Extract Buffer

IMAQ Session In identifies the device.

Buffer to extract is the buffer to extract from the buffer list, as specified by the cumulative buffer number. Input –1 to release the currently extracted buffer without extracting a new buffer.

error in (no error) describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.

	status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
	code code is the number identifying an error or warning. If status is TRUE, code is a non-zero error code. If status is FALSE, code can be zero or a warning code. Use the error handler VIs to look up the meaning of this code and to display the corresponding error message.
	source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.

Actual Width is the width of the extracted image.

Actual Width is also the current setting for the ROI width.

Actual Height is the height of the extracted image.

In most cases, Actual Height is equal to the ROI height. When in variable height acquisition mode, this value equals the actual number of lines acquired as determined by the duration of the trigger. Refer to the NI-IMAQ Help for more information about variable height acquisition.

IMAQ Session Out has the same value as IMAQ Session In.

Image Out is a reference to the image.

Buffer Number is the cumulative buffer number of the buffer in the list that was returned in Image Out.

The image number can be different from the image number requested by Buffer to Extract if the Buffer to Extract image is no longer available.

error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.

	status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
	code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code.
	source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.

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