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Scope scale problem!!!

Hi all.

 

I´m new to labview and currently using version 8.5! My problem is as follows:

 

I am connected to a agilent DSO6014A scope through GPIB to USB cable. I used the "Fetch Analog Waveform.vi" in my program for transferring 4 channels signal from scope to PC and write average signal measurement to a file. I am able to retrieve the wave into labview but the scale is not as expected. From 4 channels I send around 2.4V dc signal (with small noise) to labview but with scaling in range 1000 -9000 with different reference (i mean all signal ground is not same in the labview program). I add the image of labview waveform output and expected output and scope output. I expect shortly 4 signal at the same ground/refence around 2.4V.

 

I don't know what to do now. Thanks in advance for your help.

 

Mustafa

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I unfortnately do not have that scope next to me and so I cannot try to replicate this on my end.  However Things that I would verify are:

 

1. Verify that you are actually getting the signal that you are expecting at your Oscilloscope. with either the scope display or another scope that you may have present. 

 

2. Connect a known voltage to your Scope (1.5 V battery or something different to verify that we can pull that voltage in appropriately).

 

3. Write a quick VI with the Agilent Driver to do a simple voltage measurement from 1 channel and gets either 1 value or subset of waveform data to verify that that work sproperly - making it a problem with your VI instead of the acqisition process

 

 

I would give these couple things a shot and see what is actually causing this to occur.  Let us know of the results of these troubleshooting steps.

 

 

Charley Dahan

Global Account Manager
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Hi Mr. CharlesD , now i realized that when i worked with a simple vi of scope "ag6000a read single waveform.vi"  without no configuration,

i see 1.5V signal which i saw at scope (in scope, average measurement) around 3600 or scaled and then close end open scope or program i dont knw how after some process same process with the some tools guess what i get 1.5V at labview program on pc. How can it be? Same program once show scaled value and than return to normal.

 

Thanks...  

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It sounds like you got this setup working with the ag6000a read single waveform.vi.  Were you able to get it to work with the other funcitons. Is it in a different program.

 

If you would like some help with this please elaborate clearly- explaining in dtails what you are seeing and which functions you are using and what result you see.  Unfortunately Im' unable to properly understand your post above and am not able to provide any troubleshooting steps. 

 

Thank you

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First, Thanks for your answer. 

"It sounds like you got this setup working with the ag6000a read single waveform.  Were you able to get it to work with the other functions...."

Yes, let me explain the situation again. There is this "ag6000a read single waveform.vi" implemented to simple reading came with scope instrument driver. To my scope i simply send1.5V and see this on the scope screen as 1.5V no problem, when i transfer this signal to that vi, on the waveform graph i get signal around 3600.  After some time reset the labview and scope, and open again, and i see now 1.5V interestingly. 

 

As the situation is weird it was hard to tell the problem. But thanks again for your attentions.


 
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