Operation Principle - Microsensor MPM489W Operation Manual

4 Operation Principle

The measuring element of transmitter is a sensor, which transfers the
pressure into electric signal by semiconductor silicon material's
piezo-resistive effect. The measured pressure acts on stainless steel
diaphragm, and then be transferred onto sensitive chip by silicon oil
which is filled between the stainless steel diaphragm and sensitive chip
(see Fig. 3). The sensitive chip is connected with transmitter special
amplifying circuit by wires (see Fig. 4). Due to the good linearity
relationship between the electric signal of Wheatstone bridge on the
sensitive chip and the measured pressure, the pressure could be
measured accurately.
Fig. 3
The basic principle of level measurement is that the liquid static pressure
which proportioned with the liquid depth is transferred into current (or
voltage) signal output, and establishing the linearity corresponding
relationship between electric signal output and the liquid depth to
blue
R1
black
R2
red
R5
white
R4
yellow R3
amplifying circuit
5
-OUT
+
+IN
+OUT
-
-IN
Fig. 4