Monitor and save voltage data at input channel (NI 9263)

[msmartei]

Hi,

I'm trying to build  a VI  that ramps up the voltage output to 2 piezos, via an NI 9263. I need to be able to monitor the voltage at the piezos in order to assess their response to it. The current method only gives me the voltage at the NI 9215 which doesn't show the piezo voltage response.

Any ideas on how i can do this? 

I have attached the VI below (pardon the clutter)

I will appreciate any help i can get!

[Dennis_Knutson]

Your terms are absolutely backwards. The 9263 is an output device and I would presume what you are using to drive the piezos. The 9215 is an input device and I would imagine this is what you are using to measure the piezo response. Your code does not even measure the response of the piezos. You have this in a DAQ Assistant and that's inside a sequence structure. The acquisition is done before you even start the analog output so there is no way for you to measure the response with your current program.

[msmartei]

My use of backward terms aside, you get the general idea of what i am trying to do :).

From your reponse, it seems like i am sort of on the right track with using the DAQ assistant. How do i synchronize the data collection with the data writing to the piezos?

Or is it possible to make the DAQ assistant in the structure run for a longer period of time.

If not, how would you do measure the response?

[Dennis_Knutson]

From my response, it should seem that you are on the wrong track.

Take a little time to look at the example code that comes with LabVIEW. There is one called Multi-Function-Synch AI-AO.

[msmartei]

I implemented part of the VI from the Multi function synch AI-AO. It works to an extent but the data is cyclical, so that it pots the same graph over and over again. This isnt an important problem but i would like to know why that happens.

Also, im trying to display both channels for the 2 piezos on the graph. Is this possible? The current plot that i am getting shows both plots as being the same one. Am i just specifying the wrong channel?

Attached is the modified VI.

Thanks!