DAQmx Control Task

DAQmx - Data Acquisition VIs and Functions

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DAQmx Control Task

Alters the state of a task according to the action you specify.

If error in indicates that an error occurred previously, this VI executes normally if action is unreserve or abort.

DAQmx Control Taskc.gif

Place on the block diagram.

Find on the Functions palette.

task/channels in is the name of the task or a list of virtual channels to which the operation applies. If you provide a list of virtual channels, NI-DAQmx creates a task automatically.

action specifies how to alter the task state.

abort (6)	Aborts execution of the task. Aborting a task immediately terminates the currently active operation, such as a read or a write. Aborting a task puts the task into an unstable but recoverable state. To recover the task, use DAQmx Start to restart the task or use DAQmx Stop to reset the task without starting it.
commit (3)	Programs the hardware as much as possible according to the task configuration.
reserve (4)	Reserves the hardware resources needed for the task. No other tasks can reserve these same resources.
unreserve (5)	Releases all previously reserved resources.
verify (2)	Verifies that all task parameters are valid for the hardware.

error in 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. If an error occurs while this VI or function runs, the VI or function 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 is the error or warning code. The default is 0. If status is TRUE, code is a negative error code. If status is FALSE, code is 0 or a warning code.
	source identifies where an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

task out is a reference to the task after this VI or function runs. If you wired a channel or list of channels to task/channels in, NI-DAQmx creates this task automatically.

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, error out 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 identifies where and why an error occurred. The source string includes the name of the VI that produced the error, what inputs are in error, and how to eliminate the error.

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