Multifunction DAQ

cancel
Showing results for 
Search instead for 
Did you mean: 

PROBLEMS WITH ANALOG INPUTS OF A PCI-6251 . RANDOM +-10V PEAKS WHILE SAMPLING

While trying to sample any analog inout signal with a PCI-6251 card, I get random peaks of +10V and -10V. The probelam appears at any sampling frequency and mode.

Is it  a sign of damaged card? Is there any solution or card replacement is unavoidable?

Thank you.

0 Kudos
Message 1 of 4
(191 Views)

Please add more information about the stuff connected to the instrument, a complete schematic of connections and describe how you're capturing the data (attach the source code).

 

Try to short all AI to AIGND and see if you're able to observe the +/-10V spikes, if you do not observe, then it is a problem external to the card. To ensure your implementation of DAQmx drivers is not the bug please try this on the soft front panel.

-Santhosh
Semiconductor Validation & Production Test
Soliton Technologies
NI CLD, CTD
LabVIEW + TestStand + TestStand Semiconductor Module (2013 - 2020)
NI STS for Mixed signal and RF
0 Kudos
Message 2 of 4
(186 Views)

I have been using the card to measure current at two points of an electromechanical system by means of two corresponding resistors and measuring voltage drop through resistors. Typical level were in the range of 2 to 3 V. Measurement was performed in differential form and using a bias resistor connection between AI (-) and AIGND. I have not found any problem in this case.

Currently,during a student training session y have connected a signal generator to AI in the same way an the related problem has started. I perform measurements of AI ( only one channel) starting with a sine signal of 1V amplitude and 50 Hz and the problem appears.

I will check tomorrow as you suggest.

Thank you

0 Kudos
Message 3 of 4
(165 Views)

Please share the exact schematic of connections and their potentials.

 

If not properly connected, it is highly possible that you're damaging the instrument by applying a higher common-mode voltage where the differential is still within limits.

-Santhosh
Semiconductor Validation & Production Test
Soliton Technologies
NI CLD, CTD
LabVIEW + TestStand + TestStand Semiconductor Module (2013 - 2020)
NI STS for Mixed signal and RF
0 Kudos
Message 4 of 4
(147 Views)