Understanding Timing Options in the Simulate Signal Express VI

Issue Details

I am using the Simulate Signal Express VI in LabVIEW to generate waveform data, but I am unsure how the Timing options affect the generated waveform. In particular, I am confused about the Integer number of cycles and Simulate acquisition timing options, and how these settings impact waveform continuity and timing when the data is used for analog output.

Solution

The Simulate Signal Express VI generates waveform data based on signal and timing parameters. The following explains how the key timing options affect waveform behavior and how to configure them for analog output use.
 

• Samples per second and Number of samples define how the waveform is represented and how much data is generated.
  The total duration of the waveform is:
  
  Seconds of Data = Number of Samples / Samples per Second
  
  For example, 1000 samples per second with 100 samples generates 0.1 seconds of data.

• Enabling Integer number of cycles ensures the waveform ends on a complete cycle. This prevents discontinuities when the waveform is repeated in a loop or written continuously to an analog output buffer.
  When this option is selected, the VI may adjust the number of samples to achieve an integer number of cycles, which can slightly change the actual frequency. If needed, clear Automatic and manually increase the number of samples to improve frequency accuracy.
   
• Reset Signal controls waveform continuity between successive calls to the VI. Select Use continuous generation to preserve phase and timing information across iterations, enabling smooth, continuous output at an exact frequency without requiring an integer number of cycles. Select Reset phase, seed, and time stamps to restart the waveform from a known state on each execution.
  
   
• By default, the VI generates data as fast as possible. Selecting Simulate acquisition timing forces the VI to wait the appropriate amount of time to mimic real hardware acquisition. This is useful for simulation or demonstrations but not recommended when driving analog output hardware.
  When wiring the Simulate Signal Express VI directly to a DAQ Assistant Express VI configured for continuous analog output:

• • Avoid discontinuities by using Integer number of cycles or Use continuous generation.
  • Do not enable Simulate acquisition timing.
  • Enable Use timing from waveform data in the DAQ Assistant so the output task honors the waveform timing.