The amplitude of physical variables are converted into measurable parameters by
sensors. The measurable parameters can be a visual indication, or an electrical signal
which can be used as an actuator control signal or as a signal to a controller.
Many sensors do not have a linear relationship between physical variable and output
signal, and are temperature-sensitive. The output signals need to be corrected
for the nonlinearity in their characteristics or conditioned for transmission, so that
the necessary valves or actuators can accurately corrected for variations in the measured
variable in a process control system. Signal conditioning refers to modifications
or changes necessary to correct for variations in a sensor’s input/output
characteristics.