Generating voltages in different channels with different intervals at 6733 card

[MELSS]

Dear Friend,

       In one of our on going project, we are using NI-6733 card for generating various voltages [for. 0.048 VDC, 1.559VDC, 2.533 VDC etc].  My doubt is how to generate these voltages (for e.g. Amplitude : 1.559 VDC, Waveform type : Sinwave, Voltage range : ± 10VDC, Frequence : 1000 Hz, Samples per Buffer : 3000, Cycles per Buffer: 15.00) in A0, A1 and A2 channels with different starting time. The waveform starting time between A0 and A1 channels is 0.4 Seconds and also A0 and A2 channels is 0.8 seconds. We are using Lab view 2011 for developing this application. Herewith I enclosed the sample application having 2 channels. When I was run this code, am facing the error as

Error -200479 occurred at DAQmx Start Task.vi:2 

Possible Reasons:

Specified operation cannot be performed while the task is running.
Task Name: _unnamedTask<17>

With thanks and regards,

R. Johnson

Senior Software Engineer,

MEL Systems and Services Ltd.,

Perungudi, Chennai – 600 097.

Phone : 044-24961903 / 04.

[MELSS]

Dear Friend,

       In one of our on going project, we are using NI-6733 card for generating various voltages [for. 0.048 VDC, 1.559VDC, 2.533 VDC etc].  My doubt is how to generate these voltages (for e.g. Amplitude : 1.559 VDC, Waveform type : Sinwave, Voltage range : ± 10VDC, Frequence : 1000 Hz, Samples per Buffer : 3000, Cycles per Buffer: 15.00) in A0, A1 and A2 channels with different starting time. The waveform starting time between A0 and A1 channels is 0.4 Seconds and also A0 and A2 channels is 0.8 seconds. We are using Lab view 2011 for developing this application. Herewith I enclosed the sample application having 2 channels. When I was run this code, am facing the error as

Error -200479 occurred at DAQmx Start Task.vi:2 

Possible Reasons:

Specified operation cannot be performed while the task is running.
Task Name: _unnamedTask<17>

With thanks and regards,

R. Johnson

Senior Software Engineer,

MEL Systems and Services Ltd.,

Perungudi, Chennai – 600 097.

Phone : 044-24961903 / 04.

[cirrusio]

Hello R Johnson,

The reason that you are getting this error is that you can not access the same card through two different tasks on the 6733.  Unfortunately, if I am not mistaken, to do what you would like to do you will have to continuously update the output in the VI for each of the channels.  I can't remember how large the buffer is on the 6733, but I believe that it is fairly small so this could be a problem depending on what you are using to drive the 6733 (especially since you will have to generate > 2kS/s for 8 channels).  I don't think the problem is insurmountable, but it is definitely not as straightforward as plopping down one of the example VIs.  Have you considered using an R-series board?

Cheers, Matt