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Instrument Control (GPIB, Serial, VISA, IVI)

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Oscilloscope latest sample odd

I'm using VISA to get a waveform from RIGOL DS1054 oscilloscope and I am seeing a weird occurance when I view the waveform on the graph in my VI.

The terminal amplitude of the waveform is not the same as the oscilloscope (and also very weird looking). I tried with just measuring noise and also using a function generator to create a good sine but it can be clearly seen on both of them.

I took a screenshot so you can see 

why.png

It's definitely occuring between the SCPI of the oscilloscope and somewhere in LabVIEW because the display of the oscillscope looks fine and it is nowhere to be seen. What's really weird is that this is the untouched certified LabVIEW VI for the RIGOL oscilloscope.

 

I also had a similar problem where I was reading waveform data out of system exec function stdout and plotting it to a graph where the last sample always went straight to 0. I'm not sure if this is related or not

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What does the SCPI data look like and how is it being converted?  It looks like something is being converted to Infinity or something like that.


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That could be an offset by one error. I. e. a data array index goes from 0 to n-1 but you are trying to access it from 1 to n.

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