problem for PXI 6115 voltage generation when I try change the amplitude during the loop

[Young365]

Hello everyone,

I bought a new multifunction card PXI 6115 and I want to test the voltage generation function.

As the fugure below, I wrote a simplist wave generation program.  I set the amplitude to 1 and start the program. It can actually generate a sine wave. But when I change the amplitude to 2 while the program is running, the card can not generate the new wave with amplitude 2V. Earlier I have used cDAQ NI 9263 for analog voltage generation with the same program. But there was no such problem. For attachment I also wrote a program without DAQ assistant, in whch I also specified the write buffer.

Best regards

Yang Sun

[WaiLee]

Hi,

I'm unable to open the VI that you have attached but I have try to find relevant link here.
Did you try this link before (On The Fly Waveform Configuration with DAQmx) :

https://forums.ni.com/t5/Example-Code/On-The-Fly-Waveform-Configuration-with-DAQmx/ta-p/3491040?prof...
The link provided contain some samples VI too.

[Young365 · Accepted solution]

I found the solution. It is because PXI 6115 have a large buffer size. So before the write task on board buffer size should be set. (I don't know what's the difference between buffer size and on board buffer size.) Then everything goes well.