DAQmx Base Question

[dmourer]

I just got a USB-6008. I am trying to create a function generator. I have never used the DAQmx Base drivers and am having trouble with updating the frequency of the waveform. Can somebody give a hint. Thanks in advance.

[Matt_S.]

Are you able to adjust the frequency before you start the application (i.e. does the DAQ start to produce the frequency you set before you start the VI)? Are you only having problems adjusting the frequency once the generation has begun? Are you able to see any change in the frequency(is the change just delayed)? Are you getting any error messages?

I don't have a 6008 available, so I can't run your application to see the results you're seeing. I am going to try to get one Monday to test out the code you posted.

-Matthew S.
-National Instruments

[dmourer]

The frequency generated on ao0 and ao1 is always the same (~1.7 Hz)regardless of value entered in Desired Frequency control. Thanks.

[AlanArmstead]

Hello dmourer,
I believe your problem lies with the inputs you choose for the "Basic Function Generator.vi". It has to do with how you are calculating the sampling info inputs. You can see the frequency change in your VI a couple different ways. 1) Move your "Samples A Cycle" input inside the loop and change it dynamically. Or 2) Change the sampling info input to the Basic Function Generator.vi to be constants, then change your frequency input. Hope this helps.
-Alan A.