Endress+Hauser Prothermo NMT81, Руководство по эксплуатации

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Installation Prothermo NMT81
22 Hauser
5.8.1 Water level measurement in the three layers condition
When measuring the water level with three layers (air, product, and water) present in the
range of the water bottom (WB), the accuracy of the water level measurement is
negatively influenced by the dielectric difference between air, product, and water.
NMT81 compensates for this influence by comparing the product level from NMS8x or
NMR8x. NMT81 also eliminates the influenced dielectric difference with this
compensation result so that the water bottom (WB) maintains high probe accuracy and
stable measurement.
A
B
C
a
b
c
A0042784
 12 Water level measurement in three layers
A Air
B Product
C Water
a Low dielectric
b Dielectric
c Conductivity
50
(1.97)
0
-50
(-1.96)
-100
(-3.94)
-150
(-5.9)
-200
(7.87)
-250
(-9.84)
-300
(-11.81)
-350
(-13.78)
-400
(-15.75)
-450
(17.72)
Fuel Crude Gasoline Diesel
Heating oil
Probe length = 2.0 m
(6.56 !)
Probe length = 1.0 m
(3.28 !)
Probe length = 0.5 m
(1.64 !)
Maximum Err
or of
w
at
er le
vel mm (in)
A0044242-EN
 13 Effect of the three layers compensation