Sensors are notoriously temperature sensitive, i.e., their output zero as well as
span will change with temperature, and in some cases the change is nonlinear.
Variables are also temperature sensitive and require correction. Correction of
temperature effects requires a temperature sensitive element to monitor the
temperature of the variable and the sensor. The temperature compensation in
analog circuits will depend on the characteristics of the sensor used. Because
the characteristics of the sensors change from type to type, the correction for
each type of sensor will be different. In digital circuits, computers can make the
corrections from the sensor and variable characteristics using temperature compensation
look-up tables.
Other compensations needed can take the form of filtering to remove
unwanted frequencies such as pick up from the 60-Hz line frequency, noise or
radio frequency (RF) pickup, dampen out undulations or turbulence to give a
steady average reading, correction for time constants, and for impedance matching
networks.