problem with ps2000_fast_stream.vi

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R2TheG
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Joined: Tue Jan 21, 2014 2:55 pm

problem with ps2000_fast_stream.vi

Post by R2TheG » Tue Jan 21, 2014 3:16 pm

Hello,

I'm recently working with the picoscope 2204 and labview. I want to make use of fast streaming mode in Labview. I tried running the example ps2000_fast_stream.vi to get a feeling how it works, but it seems to have a bug in it.

The following problem is occuring: I set the sample interval to 1us, the input of the scope is connected to nothing so the output that one would get should be only the noise of the scope(around zero). When I run the Vi it starts out fine but after a few seconds I get jumps to -1V (range is one V). When I try to debug the vi this can be traced back to right after the SetBuffer block where the output is occasionally (2^16/2), the lower limit of a singed 16 bit integer. Increasing the buffersize does not seem to help much.

Attached are two images that show how the output looks and how it should look. Does anyone have an idea what the problem is and how to fix it? (it sound like a buffer overflow but I do not know how to fix it)

Kind regards, Roelof

Bugged output:
buggedoutput.png
Wanted output:
correctoutput.png

Hitesh
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Re: problem with ps2000_fast_stream.vi

Post by Hitesh » Thu Jan 23, 2014 10:39 am

Hi R2TheG,

We have been investigating issues relating to capturing fast streaming data through a wrapper dll for applications such as LabVIEW and MATLAB. What you are seeing is a value corresponding to lost data.

Please could you e-mail support@picotech.com and we will help you through the process of acquiring the data.

Regards,
Hitesh

Technical Support Engineer

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