Generating Data with an NI-DAQmx Device

You can generate any time domain signal in the LabVIEW SignalExpress project with any NI-DAQmx-supported analog output device installed on your system using the DAQmx Generate step. Before you can generate a signal using a DAQmx device, you must first create or import the signal into LabVIEW SignalExpress and then pass the signal to the DAQmx Generate step. You can create the time domain signal using the Create Analog Signal step or you can import it into your project using a snapshot, data log, or the Load from ASCII, Load from LVM, or Load from SPICE steps.

Configuring the DAQmx Generate Step

From the DAQmx Generate configuration view, you can access most of the device configuration parameters, such as the output channel, the output range, and the update rate. By default, the update rate at which the device is configured matches the sample rate of the input signal defined in the Create Analog Signal, Load from ASCII, Load from LVM, or Load from SPICE steps. You can overwrite the update rate with any value by removing the checkmark from the WT checkbox and entering a value for Rate (Hz). You can synchronize multiple boards to use the same trigger signal by setting up a digital start trigger and specifying the trigger signal of another device as the trigger source. You also can share clock and master timebase signals to synchronize multiple devices.

Generate Continuously Versus Generate N Samples

To successfully generate signals with the DAQmx Generate step, you must understand the relationship between the generation timing modes and the LabVIEW SignalExpress run modes. The following table describes how the Generate Continuously and Generate N samples timing modes work in relation to the Run Once and Run Continuously modes.