generating analog signal using usb 6008 DAQ Card

[Abuzar]

Hello,

After following the document Signal Generation Using NI-DAQmx for generating an analog signal of variable voltage and duty cycle. I wanted to send a simulated signal of ni express through ni usb 6008 daq card.

But unfortunately its not working. the Error i am having is in timming daqmx vi.

i therefore need guidence how to solve this issue.

i shall be very thankful to you.

[GerdW]

Hi Abuzar,

the error description is pretty clear: you try to setup the AO to use the waveclock sample frequency, while it only supports "on demand"...

Please read the manual of the USB6008 (page 16 and 21)! It only supports "on demand" access of the AOs, which means: DAQmxWrite set to "1 Sample" and no additional DAQmxTiming...

[Abuzar]

Thanks GredW

Its still unclear how to change the selection to on demand as it is not available in the properties.

Regards

[Dennis_Knutson]

As Gerd said, you do not use a DAQmx Timing function. You don't use DAQmx Write set to anything except 1Samp. The DAQmx Write has to be in a loop where you index the waveform array one sample at a time.

[Bob_Schor]

In particular, note that this limits the speed at which you can output points to something on the order of 100 Hz (as you need to do a USB "write" for every point).  The 6008 has a clock that can drive the input of analog samples (giving you the data "all at once"), but no similar clock for analog output.  For that, you need more sophisticated hardware (MyDAQ can do this, but it has an on-board Digital Signal Processor ...).

[Abuzar]

Thanks to all of you.

Can you pls specify the Hardware suitable to output an analog waveform of the given frequency.

Regards

[Dennis_Knutson]

You don't want to use the MyDAQ hardware mentioned in the previous post?