Saturation

Every sensor has its operating limits. Even if it is considered linear, at some levels of the input stimuli, its output signal no longer will be responsive. A further increase in stimulus does not produce a desirable output. It is said that the sensor exhibits a span-end nonlinearity or saturation (Fig. 2.6).

 Fig. 2.6. Transfer function with saturation.

Fig. 2.7. (A) The repeatability error. The same output signal S1 corresponds to two different input signals. (B) The dead-band zone in a transfer function.