G4 Multi Channel Weighing Instrument. PM/DT/HE Technical Manual

G4 Multi Channel Weighing InstrumentHints and examplesFirst of all it is important to have a good weighing application where you usethe load cells in a good way to get high resolution and accuracy. It is possibleto 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 cellsas possible.Example:We assume that you can calibrate the scale to get a stable weight reading withresolution 0.2 kg (use longer filter time if necessary).The flow rate function measures the weight difference during one derivation timeand 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/hyou will get an error of:72 / 1500 = 4.8 % for a derivation time of 10 seconds and7.2 / 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 needto have a stable weight) then you can achieve a better flow rate accuracy and/or ashorter derivation time.NOTE!The flow rate calculation is not depending on the final selected weight resolution.5-17