Vishay G4, Техническое руководство, Страница: 103 / 200

G4 Multi Channel Weighing Instrument
5-17
Hints and examples
First of all it is important to have a good weighing application where you use
the load cells in a good way to get high resolution and accuracy. It is possible
to use long filter time in the instrument to get a higher resolution and accuracy.
To get rid of noise it’s important to have as high signal from the load cells
as possible.
Example:
We assume that you can calibrate the scale to get a stable weight reading with
resolution 0.2 kg (use longer filter time if necessary).
The flow rate function measures the weight difference during one derivation time
and we assume that we can get a weight error less than one weight division.
•
A derivation time of 10 seconds gives a flow rate error of:
0.2 / 10 = 0.02 kg/s (72 kg/h)
•
A derivation time of 100 seconds gives a flow rate error of:
0.2 / 100 = 0.002 kg/s (7.2 kg/h)
In an application where you have a nominal flow rate of 1500 kg/h
you will get an error of:
72 / 1500 = 4.8 % for a derivation time of 10 seconds and
7.2 / 1500 = 0.48 % for a derivation time of 100 seconds in this example.
If it is possible to calibrate the scale with a better resolution (you still need
to have a stable weight) then you can achieve a better flow rate accuracy
and/or a shorter derivation time.
NOTE!
The flow rate calculation is not depending on the final selected weight resolution.