NI USB-6008 negative voltage

[Coq_Rouge]

So how are your full setup. Can you draw a schematic. And also which version do you use. It it the one with amplifier or not? If you do not use the version with amplifier, what do you use as excitation voltage for the bridge. And what signal levels do you expect to see

[Ajtimstoj]

Ok, i think working now, the output of sensor are from 0V (0kg, 0 N) --- 10V (1000kg, 10000kN) .

Now the sensor are not presed and the voltage are the same virtual and od multimeter.

I paste some measuremts results in image, the measurements jump to -0,019244, -0,009052 ,-0,019244, -0,009052 it is possible to stop this oscillation?

I use LabView 2010 evaluation version

[Tamas_Szekely]

Dear Ajtimstoj,

I'm glad that you managed to make it work.

I read through your attached datasheet of your sensor.

It says: Zero balance at KT1501 is 0.15% Full Scale. So it means 10V * 0,15 * 0.01 = 0.015 V fluctuation. This error is described by your sensor datasheet.

Theoricly you cannot achive more accurate measurement, than your sensor is. 

But there are some tricks to make your data in nicer representation, and eliminate the "noise".

To avoid the fluctuation of your value in the measurements, you can utilize some averaging of your data. Collect multiple data with finite or continues measurement

and you can use Waveform functions:

Or you can use multiple iterations of single point measurements and build an array of them, if it's not built yet. Then you can use Array functions to Sum up the values, and devide the result by the size of the array:

I hope I could give you some ideas, why is this "oscillation" and how to handle it.

I wish you good luck with your further development!

Best Regards,

Tamas Szekely

Applications Engineer

National Instruments

[Ajtimstoj]

Thanks guys, but now i have different problem 🙂 how can i speed up the measurement, i attach my VI program.