PCI 6534 problem with input samples

[Seyar]

Hi everyone, I'm using a PCI 6534 for some input and output applications in buffered mode.
I have a simple sampling application using the PCI 6534 board with a sampling rate of 20Ms/s. As you can see int the files below, I want to sample a clock signal generate from an external device. This clock signal is at 100kHz.
 
Sampling at 20MHz generats a bad spy file as you can see in the file file_bad.txt
 
Taking into account only one sample per two, I have a good spy file file_good.txt, but with that method I have only half of the samples, so like sampling at 10MhZ instead of 20MHz .
 
My clock signal is connected to DIOC0 and there is nothing connected to the others lines.
 
I don't know what is wrong.
 
Thanks for helping.


acquisition.zip:
http://forums.ni.com/attachments/ni/70/7135/1/acquisition.zip

[Seyar]

Nobody can or want to help me ?
please.......
 
 

[Mohamed H]

Hello,
Can you include in the zip file your VI and the method used to write in the two files.
Regards

[Seyar]

Hi, my problem seems to be more complicated !
I tried to sample the DIOC0 connected to GND : the samples are 01010101 in stead of 00000000...
More !
I noticed that this problem of having 0101010 in stead of 00000000 is not permanent.
When I start the PCI 6534, alone, with nothing connected to the card, but the GND in the DIOC0, it makes that sampling errors, and after a moment, without changing nothing, the problem dissapear, and the card samples are ok.
Is there a problem with my card ?
The card is a new one I buy since 3 weeks !
Does anyone met this problem ?
Help, please.................!!!

[Mohamed H]

Hello,
I do not have VB6 so I cannot look at your application. How did you configure your task (DIO task or counter task) and what is your source for the GND?
Regards.

[Seyar]

The two code used to make the sampling are in this picture :
the first sample at 20MHz with errors,and I keep only one sample per two.
the sample at 20MhZ also, 
 
The GND is given by an power supply, and at the oscilloscope the 0V is clean !
The pin 10 of the card (GND) is also connected to GND.
 


acquisition.JPG:
Loading Image...

[Mohamed H]

Hello,
Did you try to do the same thing in Measurement & Automation Explorer by creating a task?
Regards.

[Mohamed H]

Hello,
It seems to be an incorrect behaviour of the device. Please contact NI to repair the card.
Regards.