Whenever I try to reset the Sampling rate I receive an error from DAQ as -88700

[Sreekantha]

I call this function DAQmxResetTimingAttribute (hTaskHandler, DAQmx_SampClk_Rate); to reset the sampling clock rate after the waveform is generated. I receive immediately an error message on execution of this function with value -88700.
NON-FATAL RUN-TIME ERROR:   "voltSrc_niDaqMx.c", line 1636, col 31, thread id 0x0000028C:   Function DAQmxResetTimingAttribute: (return value == -88700 [0xfffea584]). An internal error occurred. Task Name: AO_TASK_M6251_ 0  Status Code: -88700What would be the problem? How should I solve it?

[Zach Hindes]

That is definitely not something that you should be seeing.  What device are you seeing this on?

[Sreekantha]

I am using NI DAQ PCIe 6251 Card. I usually get these type of messages and some more all related to some way or the other to samping time attributes. I am little confused and how I should carry out the configuration for generating an arbitrary waveform on the analog output. I have tried all NI examples and still it doesnt meet my requirements.
I need to generate the waveform either in continuous mode or a finite cycles. Can I know what are the necessary configuration i need to make for generating the waveform and also there are cases where I need to load different waveforms one after the other onto the buffer. When I try to load the next waveform to the buffer I get again DAQ errors.

[Corby_B]

Hello Sreekantha, Thanks for your post!  Are you resetting the timing attributes everytime you want to send a different signal? If this is the case then you would have to stop and clear the task and then reconfigure it. So there is a software approach that can do what you want to do. We don't usually do this but take a look at the attached VI. (LV 8.5) This allows you to change the frequency and wave form on the fly. You just have to be sure tha the sample rate you set the AO for is higher by at least 10 times than the frequency you want to output. Let me know if this is what you were looking for and have a great day! Cheers! Corby_Bhttp://www.ni.com/support 


Change Sine, square, tri OnTheFly 6251.vi:
http://forums.ni.com/ni/attachments/ni/250/42300/1/Change Sine, square, tri OnTheFly 6251.vi

[Sreekantha]

Hello Corby, Yes I do the same changing the waveforms one after the other on the analog output but this I do with LabWindows/CVI programming. Therefore the frequency changes and also the amplitude. Also the waveform would not be any sine or suqare etc but an arbitrary waveform. I have prepared separate GUI to ahndle this waveform and when I exit back to caller UI, there I have setting of single DC voltage. So when I return back to this GUI and try to set this single votlage point I do get again an error related to sampling attribute. So I feel there is something missing with respect to setting of sampling attribute. Would it be possible that I get typical example on how to configure and re-configure the sample timing attribute on Labwindows/CVI? Thanks & RegardsSreekantha S

[Corby_B]

Hello Sreekantha, Thanks for your post back! I apologize for my last posting of a LV example as is see now that you are using CVI. :smileyhappy: I would like to point you to an example program that is very similar to what you want to do. It does do different waveforms but adding the ability to set a DC level shouldn't be to hard to implement. Take a look at the example Mult Volt Updates-Int Clk.prj. You can find this by opening the CVI example finder. In CVI go to Help >> Find Examples and look under Hardware Input and Output >> DAQmx >> Analog Generation >> Voltage >> MultiVoltUpdates-IntClk.prj. Let me know if this is what you were looking for and please post back with other questions you may have! Cheers! Corby_Bhttp://www.ni.com/support