DT9834-8-4-16-BNC DAC output through LabView/LV-Link3 question

[TAnd]

For testing purposes, I am trying to generate a sine wave through DAC Ch0 on my DT9834-8-4-16-BNC using the LV-Link3 VIs in LabVIEW. With my program, using 2000 samples, a sine wave with one full cycle is expected. Attached below is an image of the output at DAC Ch0 from my oscilloscope and my current LabVIEW program. Any advice on what I am doing wrong? 

Also, I was wondering if there was a limit to the file size input. The FIFO is limited to 128kSamples/total, but there is no documentation on if there is a maximum file size input through LabVIEW that might cause a buffer overflow, I'm assuming there isn't one as long as the input file remains within the sampling limitations, but I wanted to verify this.

Thank you for the continued support.

 

 

Edited September 1, 2023 by TAnd

[DAQman]

I made a custom CSV file containing four waveforms - sine, triangle, sawtooth, and square. The waveform amplitudes are less than +/- 10 volts.  Attached is a new version of DtInitDACBuffers modified to work with four channels. Could you run the attached example with my csv file and verify that you see the correct waveform on every channel? 

 

 

CSV_DAC_DT9834_LabVIEW.zip

[DAQman]

I think it should work. What does the data look like in a Waveform Chart, and what is the Analog Output update frequency? Is the NumQueued Out terminal on the Write VI indicating the data is buffered? 

You could run the DtAoutWaveform.vi or the DtAinAoutContinuous.vi example as a test.

 

[TAnd]

On 9/1/2023 at 4:35 PM, JRys said:

I think it should work. What does the data look like in a Waveform Chart, and what is the Analog Output update frequency? Is the NumQueued Out terminal on the Write VI indicating the data is buffered? 

You could run the DtAoutWaveform.vi or the DtAinAoutContinuous.vi example as a test.

 

I ran the DTAoutWaveform.vi sample and got the expected results on my oscilloscope, a sinus wave.

I then ran the sinus wave from data points in a .csv and received the output in the first attached image, with requested data listed in the image, and still received the output in the original post on my oscilloscope.

I then ran it again with the data I intend to use and received the output from the second image (which is also as expected), but on my oscilloscope I'm seeing a waveform similar to what I was seeing with the sinus wave data.

The chart is plotting the data correctly, but somehow when the write VI gets ahold of it it's not producing the correct output from the data, it does however produce the correct output with the DTAoutWaveform example where it is not using data points to output. I noticed that NumQueued out count is increasing with each execution of the program, could the buffer continuing to fill be an issue? But I'm assuming if that were the case, it would work properly at least on the first execution. 

Thanks for the continued support.

 

 

 

[TAnd]

Still having issues figuring this out if anyone has any ideas. Thank you.

[DAQman]

Please attach your program and data file. 

[TAnd]

I have fixed the issue with outputting the single waveform using 1Chan NSamples on the DTWrite VI, it was user error as the test data is on the .csv in mV, the values had to be divided by a factor of 1000. 

[DAQman]

Thanks for letting me know. 

[TAnd]

22 hours ago, JRys said:

I made a custom CSV file containing four waveforms - sine, triangle, sawtooth, and square. The waveform amplitudes are less than +/- 10 volts.  Attached is a new version of DtInitDACBuffers modified to work with four channels. Could you run the attached example with my csv file and verify that you see the correct waveform on every channel? 

 

 

CSV_DAC_DT9834_LabVIEW.zip 35.79 kB · 0 downloads

I ran the attached example on my end, and I see all four DAC channels producing the expected output. I should be able to apply this to my use, I really appreciate the help. Thanks again.

[DAQman]

Here's a slightly better version of the DtInitDACBuffers vi. It has an input for number of channels and number of samples.

DtInitDACBuffersNChan.vi

[TAnd]

23 minutes ago, JRys said:

Here's a slightly better version of the DtInitDACBuffers vi. It has an input for number of channels and number of samples.

DtInitDACBuffersNChan.vi 14.09 kB · 0 downloads

This will be instrumental in my use, as my data samples will not always have the same number of channels, thanks. 

Would this be capable of producing more than four outputs from more than one device? From what I understand, it appears that DTOLCreateTask can address specific boards in the case of using multiple devices. My end goal is to be able to output up to 8 channels simultaneously, which will require the use of more than one of the DT9834-8-4-16 devices I have access to given the devices limitations of four output channels. If this is not possible, then potentially with a different DT device that can output the 8 channels needed?

Thank you.

[DAQman]

You can use two DT9834 and synchronize them using the external D/A clock input, which could be driven by a counter channel's output. I believe you would need to change out the timing vi for a DtOLTimingSetOutput.vi because it provides the external clock option.