How to trigger an analog waveform from a generated waveform

[Sami_EE]

Hello all, 

I have an analog waveform via DAQmx and I have created waveform shape and amplitude limits by using generated square waveforms. I am having trouble aligning these waveforms so that I can test the shape and assure that it is within my limits. 

Thanks

[Nathan-P]

What hardware are you using?  Also, could you clarify exactly what your trying to accomplish?  (whats your application)  

If I understand you correctly, you are acquiring an analog signal and you want to compare it to a square wave that you generated and are re-aquiring in the NI-DAQmx?

[Sami_EE]

Hello Nathan, 

I am using an NI 9201 analog input device to accept a square wave. This square wave is a continuous signal and I need to create a test to make sure it passes the amplitude and shape tests (0-5V and square wave) that I set. I am using the generate square waveform vi included with Labview to create upper and lower bounds however the signal is not triggered to start and therefore doesn't align with the input signal from the 9201 device. I am not reaquiring the generated signal through the 9201 device. 

Thanks

[Nathan-P]

There really isn't any method for aligning an acquired signal and a generated signal.  I looked into "Align Waveforms (Continuous).vi", but it doesn't appear to work with Square Waves.  

 http://zone.ni.com/devzone/cda/epd/p/id/5800

One method you could do is manually align the squre waves by adjusting the phase of the "Square Wave.vi".  From what I understand, that won't work for your testing since it will require interaction.  What parameters of the wave are you trying to measure and test?  Just the amplitudes?  Frequency too?

I hope this helps.

-Nathan

[Sami_EE]

Nathan,

That's what I had tried previously with the aligning waveforms and I currently have the phase adjust I was just hoping there was a better way to organize it without having to manually adjust each time.

Thanks anyways

[Nathan-P]

You can setup your DAQ task to have a start trigger on the waveform itself, then your Sampled waveform samples would always start in the same phase.