Position: Index > Linear >

Nonlinearity and span of transducers

2017-03-02 06:55  
Declaration:We aim to transmit more information by carrying articles . We will delete it soon, if we are involved in the problems of article content ,copyright or other problems.

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 arangeof 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 120?oC 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 a€“ 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.

span.gif

 

Another linear error close to span error iszero 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=?′/S100

where?′ a€“ output signal error due to nonlinearity; S a€“ output value at input point.

nonlinearity.PNG

 

If nonlinearity is known, then true linear output may be obtained using a look-up table or by altering output signal electronically.

 

 


Reprinted Url Of This Article:
http://www.scienceprog.com/nonlinearity-and-span-of-transducers/