NI PXI-5404
Triggering

NI-FGEN allows you to start generation immediately. You can also use a software trigger or an external digital trigger. If you configure the generation to start immediately, the waveform outputs as soon as the niFgen Initiate Generation VI or the niFgen_InitiateGeneration function is called. If you specify a software trigger, the generation does not start as soon as Initiate Generation is called; instead the generation waits until the niFgen Send Software Edge Trigger VI or the niFgen_SendSoftwareEdgeTrigger function is called. If you specify an external trigger, the generation does not begin until a rising edge is detected on the specified source terminal.

You can configure the trigger source by calling the niFgen Configure Trigger (poly) VI or the niFgen_ConfigureDigitalEdgeStartTrigger niFgen_ConfigureSoftwareEdgeStartTrigger functions or by setting the Trigger Source property or the NIFGEN_ATTR_TRIGGER_SOURCE attribute directly. You can change standard function properties or attributes, such as frequency, phase, and amplitude, while generating a waveform. If you configure the generation to trigger immediately, the change takes effect as soon as the property or attribute is changed. If you trigger the generation using software or an external digital trigger, the change does not take effect until the next trigger is received. For example, imagine that the trigger source is a software trigger and a generation is in progress. If you change the Frequency property or the NIFGEN_ATTR_FUNC_FREQUENCY attribute, the output frequency does not actually change until you call the niFgen Send Software Edge Trigger VI or the niFgen_SendSoftwareEdgeTrigger function again.