04-01-2007 10:12 PM
04-02-2007 11:19 AM
Hello Richard.
Thank you for posting to the NI Discussion Forums.
My understanding, and correct me if I am wrong, is that you are using a PCI-4351. If, and only if, you use that card in LabVIEW, you are seeing a very noisy signal. If you use the same card with MAX, or a different card at the customer site in both MAX and LabVIEW, you see expected behavior. Is this correct?
How wildly is the voltage oscillating? Providing an expected V and a read V would be helpful in answering this question. It could be that you are not selecting the correct input range for the 4351. The 4351 offers 6 bipolar input ranges: ±625 mV, ±1.25 V, ±2.5 V, ±3.75 V, ±7.5 V, and ±15 V. If you are measuring a very small voltage and measuring on the 15V input range, the accuracy of the card could certainly degrade.
Let us know how this goes and we will be happy to help until a resolution is found.
Brian F
Applications Engineer
National Instruments
04-02-2007 06:19 PM
04-03-2007 10:10 AM
04-11-2007 09:01 PM
04-12-2007 10:18 AM
Hello Richard.
I have looked at your code and was impressed by the producer/consumer architecture that you are using. You code is actually quite clean. There are no glaring problems, and from your summary about the code working perfectly in other locations, I doubt that the code is causing the problem. It is either the environment or the hardware. Since you have made efforts to improve the environment by moving it away from the EMC source, and saw no difference in the noise, you could be correct in the hardware being damaged during shipment. I look forward to your updates about your further testing at the field office.
Brian F
Applications Engineer
National Instruments
04-13-2007 02:53 AM