Acquiring Data with the DAQmx Acquire Step

With the DAQmx Acquire step, you can acquire analog signals using any NI-DAQmx compatible device in your system.

Configuring the DAQmx Acquire Step

From the step configuration, you can access the device configuration parameters, such as the input channels, the sample rate at which to acquire data, and the number of samples to acquire at each iteration. You also can configure more advanced parameters, such as the start trigger, the reference trigger, and clock. Finally, you can synchronize the DAQmx Acquire step with other hardware steps by configuring a digital trigger and using a trigger signal from another device as the trigger source. You also can synchronize multiple devices by sharing clock and master timebase signals.

Acquisition Timing

To acquire signals with the DAQmx Acquire step, you must understand the relationship between the acquisition timing modes and the LabVIEW SignalExpress run modes. The following table shows how the N Samples, 1 Sample (On Demand), and Continuous Samples acquisition modes work in relation to the Run Once and Run Continuously modes.

	1 Sample (On Demand)	N Samples	Continuous Samples
Run Once	The device acquires one sample and stops.	The device acquires N samples and stops. The device generates a start trigger at the beginning of the acquisition.	The device acquires N samples and stops. The device generates a start trigger at the beginning of the acquisition.
Run Continuously	The device acquires one sample repeatedly until you stop the execution.	The device acquires N samples repeatedly until you stop the execution. The device generates a start trigger at each iteration.	The device acquires time contiguous blocks of N samples until you stop the execution. The device generates a start trigger at the beginning of the first iteration.