RTX 1000H series user manual
K0297 Issue 2
3-6
3.8
Liquid Level Measurement
Gauge pressure transmitters can be used to measure liquid level in an open or
vented tank by measuring the hydrostatic pressure head. The head pressure
can be calculated by multiplying the liquid height above the transmitter
diaphragm by the specific gravity of the liquid.
The tank's volume and shape does not affect the head pressure. If the
transmitter is mounted below the zero point (minimum level) of the measured
range, zero suppression will be required.
Figure 3-4: Open tank level measurement
Calculations
Min. level
=
(1000 x 1.1) mmH
2
O
=
1100 mmH
2
O
Max level
=
([1000 + 5000] x 1.1) mmH
2
O
=
(6000 x 1.1) mmH
2
O
=
6600 mmH
2
O
Range
=
1100 to 6600 mmH
2
O
(Span
=
5500 mmH
2
O)
zero
suppression
maximum level
minimum level
sg = 1.1
1000 mm
5000 mm
6600
0
mmH
2
O
mA
1100
4
20
