PCI6111 card started to give a higher signal than expected

[Exedore]

hello, we have an axopatch 200b conected to a BNC 2090 block and a PCI 6111, and we started to realice that the signal noice we detect in the computer is higher than expected, i.e. when we use the test dummy circuit for the axopatch the signal should be 5V but we see 7V instead. This problem occurs randomly, some days is 5V and suddenly is 7V... and later is 5V again...

does somebody have any suggestion?

thank you in advance

[P@Anand]

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@Exedore wrote:

hello, we have an axopatch 200b conected to a BNC 2090 block and a PCI 6111, and we started to realice that the signal noice we detect in the computer is higher than expected, i.e. when we use the test dummy circuit for the axopatch the signal should be 5V but we see 7V instead. This problem occurs randomly, some days is 5V and suddenly is 7V... and later is 5V again...

does somebody have any suggestion?

thank you in advance

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What is the dummy circuit you use what is the output range of it?. Are you sure the output of the dummy circuit is 5V constant always?. If not Hook up a DMM with the same output that is going to the PCI card and see what is the value actually coming. I don't see anything with the card.

[Exedore]

Hello, we used the dummy which came with the axopatch and made the test explained in the user manual (Chapter 3 pages 11-13), i will ask to our technician about your questions. I´m pretty sure the problem is in the NI because i split the signal from the amplifier and connected one cable to the BNC connector linked to the PCI6111 and the other one to an oscilloscope and compared both signals. The signal from the computer with the NI interface was sometime 5V sometime 7V, while in the osciloscope was always about 5V.

[Plínio]

One possible cause is a grounding issue, in these cases some measure values can show itself different than the expected value.

You can read more about this on this link

http://www.ni.com/white-paper/3344/en

Regards,

Plínio Costa

[Exedore]

thank you plínio i wil discuss this with our technician

regards