Internal error

[johndoe1920]

Hello,

Trying to increase the "sample to read" for DAQ assitant which leads to an internal error. Attached is the screenshot of the errors. The errors do not give much information. Using Labview 2009. Is it a bug? or some issue with my vi?

Thanks.

[GerdW]

Hi JohnDoe,

you try to read two channels from two different modules: does your cDAQ support this?

Why don't you use simple DAQmx functions instead of relying on this buggy "nice" DAQAssistent?

[johndoe1920]

Yes, the cDAQ supports this. I have a cDAQ-9174 which is recently acquired.

Currently the number of samples to read is set to 100. The vi works fine with that. This errors pops up only when I try to increase or decrease the numner of samples to read.

[johndoe1920]

I moved the file to the desktop and the problem seems to have resolved itself. I initially moved this file into a seperate folder from Desktop.

But now, I am getting "Error - 200279 occured at DAQmx Read Analog 1D Wfm Nchan NSamp.vi:3". It is saying that increasing the samples might resolve this. I tried to increase it from 100 to 10000. Still I get this error. Is it because of the waveform chart? I do not really need it. Would it be resolved if I just log the data to a file? Any suggestions?

[GerdW]

Hi JohnDoe,

I moved the file to the desktop and the problem seems to have resolved itself. I initially moved this file into a seperate folder from Desktop.

I don't think this is related to your problem in any way…

But now, I am getting "Error - 200279 occured at DAQmx Read Analog 1D Wfm Nchan NSamp.vi:3". It is saying that increasing the samples might resolve this.

No, don't fiddle with buffer size! DAQmx handles this quite well on its own!

You need to read your data more often/faster/with different block sizes!

The problem most probably comes from setting a "continuous" DAQmx task, but only reading the samples based on a condition: this will fill up the buffer quite well!

Read the data ALWAYS, but only display/log them when needed. A producer-consumer-scheme might help you to implement this…

[johndoe1920]

Hi GerdW,

I converted the DAQ assistant block to DAQ mx blocks. Tweaked it a bit. I used the convert tool. It has solved the error (Error - 200279). Attached is the final vi. The power waveform is choppy. The Amplitude of voltage and current seem to be fine. Why is it so? and how do I solve that?

[GerdW]

Hi JohnDoe,

it's "choppy" because you start and stop the DAQmx task each time.

When you want to read continuously you need to run your task continuously!

Did you examine the example VIs coming with LabVIEW? They explain such things very well…

I think I need to repeat a sentence from my last message:

Read the data ALWAYS, but only display/log them when needed. A producer-consumer-scheme might help you to implement this…

[johndoe1920]

Hi GerdW,

I could not find any producer/consumer model examples from Help>Find Example. I tried with search terms producer and consumer. Anyways, I looked into google images and modified the architecture of the code. Can you please have a look at it? The power chart shows only some samples when the vi is running. I think the issue is the variable based approach. I think I need some queue based approach. Any suggestions? Thanks a lot for your time.

[GerdW]

Hi JohnDoe,

I could not find any producer/consumer model examples from Help>Find Example.

File menu -> New…

I think I need some queue based approach.

Yes.

[johndoe1920]

Hi GerdW,

Could you please check if everything is fine with the final vi? I added type double to the element data type for the "obtain queue function". Somehow the data wire color is orange. It should be blue I guess.

Also, I am getting red vertical lines on the chart. I am not sure why.

Also, could you please let me know how can I get the symbol in Capture3 attachment.