Cursors don't match what is on the scope.

[rcard53762]

I am reading a waveform from an Agilent scope. I can measure the delta time on the scope with the cursor function.

When I look at the same waveform in Lab view the timing information is wrong.

See the screen captures. I suspect its a setting in the waveform menu, but I don't know which one.

See attachments.

How do I set up labview so the vertical and horizontal scales match what is on the scope and so that the cursors will give me a delta time?

Thanks for any help.

[ABCPrograms]

I have the idea, that your cursors are not in the correct position.  YOu can right click on a cursor and select snap to single plot.  In  that case the cursor will allways point to a certain spot on that graph.

2nd, I think you are missing some points on your graphs.  If you look at the scope it is very smooth, will the graph in labVIEW has peaks.  

Kind regards,

Bjorn

[rcard53762]

Its not the position of the cursors that is causing my problem its the fact that the scales on the scope and the scale on the lab view are not giving the same values.

The waveform is a 1 KHz sinewave so measuring from 1 peak to the next should always give the same delta.

But the scale is different on the labview waveform.

How do I make the labview scale agree with the scope time/division setting?

[ABCPrograms]

Manually : By selecting the properties of the graph and go to scale.

Automatically : since you're using a GPIB comm. protocol, you should be able to send a command to the scope to give the current scaling.  After you received that, you can put it into a property node of the graph.  See attachement

Kind regards,

Bjorn

[ABCPrograms]

tried to add a snippet 😉