convert voltage to force

[rifel]

and here is the voltage value shown in the table of Labview Express task tab.

[RavensFan]

You've got 2 numbers there.  99.9 pC/mechanical unit.  The chart in the earlier message suggested -7.5 pC/N.  So is "mechanical unit" mean Newton?  Why an order of magnitude and a sign difference.

You also have scale of 10.  So does that mean you take the value you read and multiply by 10, 100, 1000?  Very confusing.

 I suggest you take a reading, add a known load, and take another reading.  Seeing how much the signal changed for the load might help you figure out what to multiply the analog input by to get your force.

That, or call Kistler.

[rifel]

thank for your replying Mr. RavensFan.

I use 3 axis dynamometer, that figure depicted the X, Y, and Z axis grinding signal, respectively. suppose the labview shows the value in 42.114 mV of Z axis. Then how to convert this value to force unit? Give advice please.

Other than that, on charge amplifier setup are: 

1. Sensitivity 9.99E+1 in pC per mechanical unit (pC/M.U)

2. SC (scale) 1.00E+1 mechanical unit/V

based on the manual information mechanical unit means e.g bar, N (newton) and g 

[GerdW]

Hi rifel,

according to your spec sheet shown above you need to use different settings for your charge amplifier!

1. Change sensitivity to 7.6 pC/m.u.

2. Set SC to 1000 m.u./V to receive a signal of 1V per 1kN…

[rifel]

Hi GerdW,

Thanks for your advice. If I got some value in Volt unit, says 0.5 mV, then how to convert it to foce unit?

Thank you

[GerdW]

Hi rifel,

have you ever read a sensor spec sheet?

1. Your sensor gives an output in pC/N.

2. Your charge amplifier is amplifying from pC to V (units), so you get V/N.

3. Now you need to apply some simple math: "xx" pC/N × "yy" V/pC = "xx × yy" V/N…

[rifel]

hi GerdW,

Thanks for your expanation.

I am new about Labview and Kistler dynamometer. I'm still confuse how to do this. Suppose, I have the value from labview 0.45 mV after machining processing, then how to convert this 0.45 mV to force unit?

Says, the settup are:

1. sensitivity 7.6 pC/m.u

2. SC (sclae) 1000 m.u/V

Thank for your advice

Best regards

[GerdW]

Hi rifel,

Such simple things are usually explained in the manuals of your sensor and charge amplifier. Read them!

I am new about Labview and Kistler dynamometer.

This question has nothing to do with using LabVIEW nor is it related to that special DAQ device: it's a basic "electrical measurement" question. Read some (basic) books about!

[rifel]

Hi GerdW,

Thank you very much for your explanation. God bless U.

Best regards.

rifel