Step Response With NI cDAQ-9172

[lockesmith]

I would like to output a prescribed voltage to a piezo actuator and record the response.  I'm not sure how to sync the AO and AI and make the graph on a time basis.  I would like to calculate the Rise Time (step response), Overshoot, and Settling Time so I need help capturing the voltage jump with a high sampling rate.

I have attached the start to my vi.

I appreciate any help/insight you can give.

Thanks

[Efrain_G]

Dear lockesmith,

I recommend you to take a look at the following shipping example offered in LabVIEW. This example will allow you to synchronize your analog input and output tasks. With this example you will be able to determine the sampling rate of your AI so that you can obtain information about Rise Time, Overshoot, and Settling Time.

Help>>Find Examples>>Hardware Input and Output>>DAQmx>>Syncronization>>Multi-Function>>Multi-Function-Synch AI-AO

[lockesmith]

I would like to add another analog input that would record at the same time as the other so that I can compare the signal I am sending from my analog output to the signal i am getting in response from my device.  How can i achieve this.  I have attached my attempt.

[lockesmith]

I think this is a rough start to something that seems to work.  I just need to figure out how to just get one iteration of the square wave.  I just want to see the voltage jump up and look at the response and other properties that i mentioned earlier.  Does the attached vi seem to make sense?

[Efrain_G]

Your code looks good. As far as getting only one iteration, you can create some software logic to focus on one square wave. You might need to know in advance which iteration of the square wave are you interested in. I would recommend you do all this in a post processing data scheme, since your application performance can be reduced if you try to analyze and compare your data while you acquire.