NI 5412/5421/5422/5441/5442
Arbitrary Sequence Trigger Modes

This topic contains information about the behavior of the signal generator in Arbitrary Sequence mode with a particular trigger mode.

Single Trigger Mode

The waveform pattern you define in the sequence list generates only once by going through the entire list and then the waveform generation halts. Only one Start trigger is required to start waveform generation. After the NI 5412/5421/5422/5441/5442 receives a Start trigger, the waveform generation starts at the first segment and continues through the last segment. After the entire sequence list has been generated, it remains at the DC level of the last sample of the last segment of the sequence indefinitely. All Start triggers after the first Start trigger that starts waveform generation are ignored.

Note  You can have the waveform finish generating at a desired DC value by making the last point in the last segment that DC value, or you can add an extra segment filled with the same DC value.

Continuous Trigger Mode

The waveform pattern you define in the sequence list generates continuously by continually cycling through the sequence list. Only one Start trigger is required to start waveform generation. After the device receives a Start trigger, the waveform generation starts at the first segment and continues through the last segment, and then loops back to the start of the first segment, continuing indefinitely. All Start triggers after the first Start trigger that starts waveform generation are ignored.

Stepped Trigger Mode

The waveforms you define in the sequence list generate one segment at a time, each time a Start trigger occurs. The waveform loops as many times as has been configured for that particular segment. After the generation of a segment has halted, the last sample of the waveform repeats continuously until the next Start trigger is received. When the next Start trigger is received, the waveform defined by the next segment generates for configured amount of loops. After the sequence list is exhausted, the waveform generation returns to the first segment and subsequent Start triggers restart the process. If a Start trigger is received while a waveform is generating, the Start trigger is ignored and another Start trigger is required to generate the next segment after the last sample generates. A Start trigger is recognized only after the segment finishes generating.

Burst Trigger Mode

Each waveform you define in the sequence list generates continuously until another Start trigger occurs. A Start trigger causes the waveform generation to switch to the waveform defined by the next segment, after the current waveform finishes. After the sequence list is exhausted, the waveform generation returns to the waveform defined by the first segment and subsequent Start triggers will restart the process. Only the first Start trigger which signals a transition to the next segment is recognized, all subsequent Start triggers are ignored until the currently generating waveform finishes.

Note  The transition of one waveform to the next can be made amplitude continuous if waveforms in all segments start and end at the same amplitude. Alternatively, this also can be accomplished by ensuring that the waveforms from one segment to the next end and start at the same amplitude. This amplitude continuous transition is shown in the previous Arbitrary Sequence Mode examples by the transitions of Segments 1 to Segment 2, and Segment 3 to Segment 4. The transition from Segment 2 to Segment 3 shows a discontinuous transition, going from a positive value on the last sample of the ramp waveform right to a midrange value of the sine waveform.