PCI-6221 AI faulty reads -11v constantly

[ShadowLurker]

hi all,

i have 3 automated pcb testing machines all with PCI-6221 boards
the problem i have was found about 6-9 months ago while i was constructing the 3rd bench where all inputs were "railed" to +11v
even with all connections removed from the PCI-6221
i had the board replaced by NI
now that these machines have been running for quite some time i have now come across one of the inputs (in this case AI0) "railed" at -11v
all other inputs seem to be fine

has anyone else seen this issue / have a fix for it or is it simply a warranty thing and should get the board replaced

regards
ShadowLurker

[Corby_B]

Hello ShadowLurker,

Thanks for your post!

I am sorry to hear that one of your inputs seems to be not working. A few questions for you, Does the same -11 volts appear is you connect an Analog Output to AI0 and then send a voltage in using the Test panels in Measurement and Automation Explorer (MAX)? Also are you able to send a voltage in from a known power supply or source. Do you still read -11 volts in the test panels if you do this? It sounds like you have used these cards before but do you see this problem in both differential mode and RSE mode for the input connection?
Let me know your findings so we can find you a solution to your problems!

Cheers!

Corby_B
http://www.ni.com/support

[ShadowLurker]

Corby_B

yes i have tried linking the AO to the input and sent singals back into it and still a -11v reading
i checked with a CRO and there was a signal at the card but it did not recognise it

this reading is fixed at -11v even if DIFF or RSE or NRSE

i normally use the card as NRSE for my audio measurements signals are protected by my input conditioning
they are pulled to ground with 100Kohm and capacitor coupled to the measuring points
i dont suspect that there was any kind of spike or excessive voltage
i have also once had a card from new do it but that was on all AI ports


regards
ShadowLurker


Message Edited by ShadowLurker on 07-17-2008 01:11 AM

[Corby_B]

Hello ShadowLurker,

Thanks for your post back!  I am sorry to hear that in any configuration you set your card to the problem still exists. It looks like the best option at this point is to have the card sent in to NI to take a look at it. Follow the link below as this is the best way to get in touch with someone that can help you. When you call in just reference this forum post and some will be able to help you.

Contact NI

Thanks for your time ShadowLurker and please post back if you have any other questions.

Cheers!

Corby_B
http://www.ni.com/support