require support regarding anaolg daq

[amit_dandi]

We are using cRIO 9063 controller with Analog module 9201(RSE) at Cummins,Pune.

As we acquire voltage signal(0V to 10V) from HBM torque transducer T40B across Pin 1(white)as GND and Pin 4(Red)as AI signal.

At normal condition sensor output gives stable voltage 0.017v on measuring fluke multimeter and fluke data logger, but in NI system it gives fluctuation from -0.021v to 0.040v.

[LocalDSP]

First of all the 9201 is a 12 bit module with fixed range of +/- 10V. It means that the acquisition resolution is approx. 20/4096 = 4.9 mV.

Then it sounds like you are referring to individual measured sample values and these will vary slightly mainly due to system noise. When you measure with the Fluke multimeter you are averaging your signal over a period of time, say 100 ms and you should do the same with your 9201 system do do a fair comparison.

Try to acquire for example 1000 samples and take the average value (mean) of your data set. With fluctuating values between + 21 and +40 mV the mean may not be far from your expected ~+17 mV.

[LocalDSP]

Actually try to average data over exactly 100 ms. The needed number of samples (N) will depend on your chosen sample rate.

N = Fsampling * 0.1 s = Fsampling / 10.

The average time of 100 ms is commonly used by multimeters and ideal to remove issues caused by main power frequency whether it's 50 Hz (5 periods) or 60 Hz ( 6 periods).