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Trouble acquisition with Picoscope3404A

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Trouble acquisition with Picoscope3404A

Postby haithem » Mon May 06, 2013 4:17 pm

Hi,
i'm trying to do a simple aquisition under Linux installed on a virtual machine "vmware", using the Test example "PS3000Acon.c" .but results are completly incoherent.
So i want to ask if anyone has tried to use pico with linux on a virtual machine.

Thanks for your help.
haithem
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Re: Trouble acquisition with Picoscope3404A

Postby Martyn » Tue May 07, 2013 2:16 pm

I have used Ubuntu on Vmware with the two channel variants in the 3000 series, not the four channel.

What do you mean by
results are completly incoherent.
Martyn
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Re: Trouble acquisition with Picoscope3404A

Postby haithem » Wed May 08, 2013 10:21 am

First thank you for your quick reply.
By incoherent results, i mean that i did'nt find the expected voltage.
infact:
I was trying to do aqcuisition of 13/18V DC Electrical Signals.
on windows i find correct results when using the refrence picoscope software which certifes a valid input signal and the hardware (the picoscpe itself)
After that i tried to do the same thing under Linux using the ps3000a Linux-DSK and the test example PS3000Acon.c
I excatly followed the instrutions given in the refrence linux software. i compile it ,as required and start doing some tests as follow:

input signal : 13V DC (connected on input A) and 18V
input B , C, D not connected.
set voltage range "V" to 20V on the 4 inputs (A,B,C,D)
perform a capture of block using block Mode capture: "B"/streaming Mode: "S"

Results:
--with Block Mode "B": the results are far from 13V/18V, the maxVoltage are negatif and the minV are positif
---But when i use the Streaming Mode "S": i note a factor of 2( for 13V , i have ~6500 mV and for 18V i have ~9000mV)

I tried to push further and investigate this use case(streaming Mode) and found that the results of the input A changes if i desactivate the non used input B,C,D i.e: i have different results on input A when i desactivate "B" set voltage to 99", or/and "C" or/and "D"

Hence even the "2" factor i noted on the streaming mode becames obsolete.

Finally i want to ask you if it is possible to give us an image of the Linux virtual Machine that you used for the test and i will be so grateful because it's a emergency for me.?


Thank you
Best regards
Haithem
haithem
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Re: Trouble acquisition with Picoscope3404A

Postby Martyn » Mon May 20, 2013 10:57 am

Sorry can't give you a copy of the virtual machine, it contains information I am not allowed to release.

What adc count values are being returned by the driver before you convert them to mV ?
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