Analog output created in labview 7.1 with the DAQ 6008

[Phoenixcabe]

I want to know how can i send a sine analog output created in labview 7.1 with the DAQ 6008 so that i can control external hardware? I know that the DAQ 6008 can't send a continuous output it has to be done by the software-timed updates but i don't know very well how to do it. I will aprecciate any help. Thanks

[Jonathan_Brumley]

You can use DAQmx Write in a loop to generate a sine wave one sample at a time.  If you want to control the timing, you can use "Wait for Next Millisecond Multiple" or you can use the LabVIEW timed loop.

However, I wouldn't recommend using the 6008 to output a sine wave.

Since every sample you write has to go over the USB bus individually, there will be a lot of variability between each update.  The USB 1.1 bus has high latency; a minimum of 1-10 ms per message written.  I expect you will be able to update the device once every 1-50 ms or so, but the exact time per update can vary considerably.  Because of the variation, the sine wave will be extremely jittery.  In addition, because of the slow update rate using USB, you won't be able to output more than 100-1000 samples a second.  You will end up having to output a _very slow_ sine wave or output a very bad approximation of a sine wave.

[Phoenixcabe]

Hi. Is there any problem if instead of using DAQmx i am using DAQmx Base? Thanks for the help.

[Phoenixcabe]

Hi. I still can't get the signal to control the external hardware. I was trying to use one of the examples but i don't know what am i doing wrong. I send an attachement of the block diagram that i am using. If you can give me any clue that would be great..thanks

[devchander]

Connect iteration count"i" directly to index array.
Or enable Auto index at the array entry point at the input of while loop

do not use/connect the 'quotinent/reminder' function's reminder result to index array.

[melvingao]

Dear Jonathan

Please recommand a USB DAQ which can generate 1kHz sinewave, Thanks

melvin