How to convert sensor volts or counts to a physical value?
04/12/22 10:29
Data Acquisition Systems (DAS) convert volts to counts but what does that mean physically? Say you have a DAS connected to an accelerometer-type sensor. The spec sheet for the accelerometer is 1 g = 2.6 volts. The DAS spec is 420,000 counts = 1 volt. So if the counts is 420,000 that represents 1 volt or 1/2.6 g. More generally the physical value is:
Acceleration (g's) = counts X (volt/count ) X (g/volt)
So if the reading is 200,000 counts, the value in g's is:
200,000 X (1/420,000) X (1/2.6) = 0.183 g
The conversion a sensor does from a physical quantity to volts is termed the "sensitivity" of that sensor. The same with a DAS, from volts to counts is the sensitivity of the DAS. A pressure sensor may have a sensitivity of P volts/psi (English pressure unit, pounds/sq. inch) or Pascal (Pa), metric, (Newtons/sq. Meter). If you know the sensitivities of the sensor and DAS you can easily find the actual physical value.
Acceleration (g's) = counts X (volt/count ) X (g/volt)
So if the reading is 200,000 counts, the value in g's is:
200,000 X (1/420,000) X (1/2.6) = 0.183 g
The conversion a sensor does from a physical quantity to volts is termed the "sensitivity" of that sensor. The same with a DAS, from volts to counts is the sensitivity of the DAS. A pressure sensor may have a sensitivity of P volts/psi (English pressure unit, pounds/sq. inch) or Pascal (Pa), metric, (Newtons/sq. Meter). If you know the sensitivities of the sensor and DAS you can easily find the actual physical value.