Difference between A and B

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astroman
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Joined: Wed Aug 19, 2020 1:40 pm

Difference between A and B

Post by astroman »

I'm a new user setting up a picscope 2204a for physics students.

I am trying to use the maths function A-B
Picoscope draws the A-B but I cant see how to expand the Y scale for the difference so I can see it. The difference is small.

Also when I click on the graph data it says A and B are the same and it gives the difference as the sum!

Also clicking the mouse on any display doesn't give a consistent voltage. The time marker is ok but on a display showing a constant voltage, very different values are shown.

eg the display is showing about 0.4 V and the cursor says 94 mV
Attachments
discrepancy between scale and cursor
discrepancy between scale and cursor
voltcheck.jpg (7.67 KiB) Viewed 929 times
A-B odd result
A-B odd result
test.jpg (16.51 KiB) Viewed 929 times

bennog
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Location: Netherlands

Re: Difference between A and B

Post by bennog »

can you post a psdata file ?

Benno

astroman
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Joined: Wed Aug 19, 2020 1:40 pm

Re: Difference between A and B

Post by astroman »

many thanks for your help
here is the file
and an example of A-B
Attachments
A-B.jpg
20200826-0001.psdata
(50.05 KiB) Downloaded 19 times

Martyn
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Re: Difference between A and B

Post by Martyn »

When you click on the display you are presented with the values that particalur point on the display would be on each axis, not the value of each trace at that time point.
Martyn
Technical Support Manager

bennog
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Location: Netherlands

Re: Difference between A and B

Post by bennog »

You can expand the y-axis by clicking on the smal box at the bottom
2020-08-26_22-10-05.png
so if you set the scale to 10 you can see the difference
Remember this a 8 bit scope.

Benno

astroman
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Joined: Wed Aug 19, 2020 1:40 pm

Re: Difference between A and B

Post by astroman »

Hi

Thanks very much for the explanation.

Perfect

I'm much obliged

Ken

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