Signal polarity specifies the polarity of the Signal input. TRUE indicates the signal occurs on the rising edge. FALSE indicates the signal occurs on the falling edge. The default is TRUE.

IMAQ Session In identifies the device.

Signal specifies the assertion edge of the signal that causes the occurrence to be set.

The following values are valid:

• Acquisition in progress—Asserts when the acquisition begins.
• Acquisition done—Asserts when the entire acquisition is finished.
• Frame start—Asserts at the beginning of each frame that is captured.
• Frame done—Asserts at the end of each frame that is captured.
• Buffer complete—Asserts when a buffer has been transferred to memory.
• External trigger 0
• External trigger 1
• External trigger 2
• External trigger 3
• RTSI line 0
• RTSI line 1
• RTSI line 2
• RTSI line 3
• RTSI line 4
• RTSI line 5
• RTSI line 6

Note  The Frame start and Frame done signals are not valid for line scan acquisitions unless each buffer is triggered.

create/clear instructs the VI to create an occurrence or to clear all occurrences that have been created for the image acquisition device specified in IMAQ Session In.

The following values are valid:

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.

Rearm? (FALSE : No Rearm) indicates whether the occurrence should be generated once, or each time the signal occurs. When you set this parameter to TRUE, call this VI again with the create/clear parameter set to clear all occurrences to stop the occurrence.

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

occurrence is the occurrence value created. Wire this output to a Wait on Occurrence LabVIEW primitive. Wire the output of the primitive to the part of your diagram you wish to execute when an event happens and the occurrence is set.

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.