Every time when developer is selecting a transducers for their projects they have to look through various parameters and select part which best fits the design needs. This time lets look at some transducer characteristics that can be found in specifications.
Transducer Range
First of all lets clear out what is a range of a transducer. Range is understand as maximum and minimum input and output signal. For instance we can take simple thermal sensor which input range can be from -50 to 120ºC and output range of 0 to 5V. Range can be understand not as only measured signal range but working environment parameters like working temperature range, power supply voltage range etc.
Full scale deflection – Span
Span is the maximum variation in the input or output. Span can variate due an error that mostly is linear and can be adjusted. Span error is measured in percents which shows how much the output value is different from correct value.
Another linear error close to span error is zero offset. This error occur because of calibration errors or other changes like aging or environmental conditions change. Zero offset error is constant over all range. It can be fixed by recalibration the transducer.
Nonlinearity
Nonlinearity describes the deviation of a linear relationship between input and output. Maximum nonlinearity can be calculated by simple formula:
Nmax=δ/S·100
where δ – output signal error due to nonlinearity; S – output value at input point.
If nonlinearity is known, then true linear output may be obtained using a look-up table or by altering output signal electronically.
