Generating a decreasing voltage output

[Bessel]

Hello,

I am trying to output a voltage signal resembling a sine wave and I have easily managed to do that using a USB 6009. However, I am having trouble steadily decreasing the signal. For example, I want to output a sine wave with an amplitude of 4 for the first 0.3 seconds, then a sine or square wave with an amplitude of 3 for the next 0.3 seconds and so on. I tried using sequences but I keep getting "Error -200088." I even added a "DAQmx Is Task Done.vi" as suggested by another discussion board and it still gives the same error. If anyone has any input whatsoever, I will really appreciate it.

Also, I am using LabView 2010 if that makes any difference.

Thanks in advance.

[egraham · Accepted solution]

See if this will work for what you're trying to do. Everytime the elapsed time VI has a time elapsed output it indexes your array count and inputs the next lower voltage to your sine amplitude.

Eric

[Bessel]

Hello,

Thank you for your help! I built the VI but for some odd reason it doesn't go to the next value as indicated by the array. My VI looks exactly like yours but it stays at the first value, ie 5, and never cycles down. Is there a way to fix this?

Thanks again!

[egraham]

It seems to be working OK on my end. Try the attached VI. You'll have to change the timing for your application. I've got it set to 1 second.

[Bessel]

I apologize but I got it to work. There was some internal DAQ error on one of our computers. I really appreciate your input. Thanks again!