How do i use AO generate waveform.vi to hold voltage constant

[Eugene Cameron]

I already have a program to ramp voltage, and i am trying to modify it so that it will ramp voltage( with a base that the user picks) and then hold it over long period of time, and then bring it back down. Someone sugested that i use the AO Genereate waveform.vi, but i am not sure how to implenment this vi to do what i want to do .

[RobertoBozzolo]

The DAQ card maintains its output until you change it or reset the device, so when you have outputted a value you simply have to wait for the desired time to expire and then lower it with the same ramp vi from the actual voltage to 0. So you program will be that way:
Step 1: output the voltage ramping up to the desired value
Step 2: while doing anything to the output of the DAQ card (neither resetting the device!) wait until time expires; in the meanwhile you can perform other tasks on the card (analog input and/or digital input or output) without affecting the output value
Step 3: Lower the output value to 0

I suppose you are referring to my reply on june 25th: if not go and look at the attached file to have an example of how to use the Generate Waveform
.

I arranged a simple llb as an example.

Roberto

[Eugene Cameron]

Thank you for your help, but if you could save the files under 5.0 format option, that would be great, because as of now, i cannot view the files, you can email them to me at elcamero@email.unc.edu

[krithika]

Hi Roberto

I went through your Vi that is posted. I see that you are able to ramp up over a period of time (few seconds) and its stays there for some time and then ramps down at the same rate but when i change the time input to the ramp i see it ramp up at the same rate. Can you pls tell me how i can control the rate at which the signal ramps up.

Thanks

Krithika

[McKala[DE]]

Hello Krithika,

To change the period for the signal to ramp up or down, you have to change the Ramp Time (sec) input in the Prepare the Ramp VI.  If you want to have the same period rising and falling, change the inputs to both of the Prepare the Ramp subVI's in the main program VI. 

Regards,