Level Probe LGC2
Product Description
2017
-0
2
15
3
Product Description
3.1
Function
The ceramic measuring cell is a dry measuring cell i. e. the pressure acts directly on the robust,
ceramic process isolating diaphragm of the device. Changes in air pressure are guided via a
pressure compensation tube through the extension cable to the rear of the ceramic process
isolating diaphragm and are compensated for. A pressure-dependent change in capacitance,
caused by the movement of the process isolating diaphragm, is measured at the electrodes of
the ceramic carrier. The electronics unit then converts this to a signal that is proportional to the
pressure and linear to the level.
Figure 3.1
1
Ceramic measuring cell
2
Pressure compensation tube
h
Height level
p
Total pressure = atmospheric pr hydrostatic pressure
r
Density of the medium
g
Acceleration due to gravity
P
hydr.
Hydrostatic pressure
P
atm
Atmospheric pressure
P
sens
Pressure displayed on the sensor
.
.
2
1
ρ x g
h ~ p
h =
p
p
hydr
p
atm
p
atm
p = p
+
atm
hydr.
p
h
p = p
+ p
atm
hydr
p
atm
Rel.: p
= (p
+ p
) -
sens
atm
hydr.
Abs.: p
= (p
+
sens
atm
hydr.
p
)
p
atm
