Generating signal from Analog Output (cDAQ/Mod4/AO) and acquiring in Analog Input (cDAQ/Mod8/AI)

[UsedThunderbolt]

The application must generate a ripetitive signal with a ripetion of waveform every second. The frequency of the waveform must be 10 Hz and it is not editable by user. The user can modify the number of periods generated in one second using "Number of Period". min value of period is 1 and max value is 5. The application acquire from channel AI1 a signal generated by channel AO0. Acquisition and generation start and the same time when occur a rising edge of the trigger PFI0. Acquisition and generation are continous.

My main goal is to be able to obtain a continous and editable generation-acquisition; I basically put DAQmx Write and DAQmx Read inside a While Loop. This was done in order to keep generating and acquiring continous even with different setting (sine, square or different amplitude and number of periods as asked), but after 1 run an error in DAQmx Read occurs:

Possible reason(s):

The application is not able to keep up with the hardware acquisition. Increasing the buffer size, reading the data more frequently, or specifying a fixed number of samples to read instead of reading all available samples might correct the problem.

Here my diagram panel in two parts (it is tooo big):

Part One  (Channel, sample and trigger settings)

Part Two (While Loop)

[GerdW]

Hi Thunderbolt,

very important rule: NEVER EVER link to images placed on some 3rd party websites like your "pasteboard.co"! Many people active in the forum might have been blocked from access due to company firewall rules!

Attachments belong to your message, using the attach feature of this board!

Images should even be inlined into the message:

Next important rule: we cannot debug images using LabVIEW! Please attach your VI(s) instead of cropped images showing only parts of your whole VI (and still hiding a lot of missing information)!

[UsedThunderbolt]

Hello GerdW,

sorry for my mistake 🙂 it will not happen again.
By the way here my .vi...hope someone can help me

[GerdW]

Hi Thunderbolt,

the first step to solve problems should be to cleanup your VI. (Follow the StyleGuide, found in the LabVIEW help!)

This way it is much more readable:

Suggestions:

• Place AI and AO tasks into their own seperate loops…
• When you want to output a waveform then you should set DAQmxWrite to expect a waveform! (Did you notice that coercion dot?)
• And never delete the label of any FP elements! (You may hide them in the frontpanel if they aren't needed there.)

[UsedThunderbolt]

Hi GerdW,

first of all thanks for your reply.
Now my VI correctly work and it is able to change amplitude and waveform during acquisition.
Can you please explain me better what really chagend? And which was my problem with write and read in the same loop?