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Levels table
Level
Level
Air
NN
NN
press.
(hPa)
1250
0
1013
1300
50
1007
1350
100
1001
1400
150
995
1450
200
989
1500
250
983
1550
300
977
1600
350
971
1650
400
966
1700
450
960
1750
500
954
1800
550
948
1850
600
943
1900
650
937
1950
700
931
2000
750
926
2050
800
920
2100
850
915
2150
900
909
2200
950
904
2250
1000
898
2300
1050
893
2350
1100
887
2400
1150
882
2450
1200
877
Level
Air
Level
NN
press.
NN
(hPa)
2500
746
3750
2550
742
3800
2600
737
3850
2650
732
3900
2700
728
3950
2750
723
4000
2800
719
4050
2850
714
4100
2900
709
4150
2950
705
4200
3000
700
4250
3050
696
4300
3100
692
4350
3150
687
4400
3200
683
4450
3250
678
4500
3300
674
4550
3350
670
4600
3400
666
4650
3450
661
4700
3500
657
4750
3550
653
4800
3600
649
4850
3650
644
4900
3700
640
4950
5000
Technical information
Air
Entering the air pressure
press.
(hPa)
In order to convert the differential pressure values, measured by the Pitot
tube, to velocity the air pressure at the measurement location is needed.
871
Before the measurement this air pressure must be entered via the
866
"COEFF.MFLOW" submenu in the unit hPa (=mbar).
861
There are 3 ways to measure the air pressure.
855
850
1. Measuring using the levels table
845
The levels table (left) indicates the air pressure absolute values under
840
normal weather conditions for the respective height above sea level.
835
830
824
Example:
819
814
809
2. Measuring the absolute pressure
804
Using a suitable absolute pressure measuring instrument the exact value
799
can be measured.
794
789
785
Note: Barometers which are fixed may be corrected to a certain level.
780
The display corresponds then to the absolute pressure for 0 m above
775
sea level and not the real current air pressure. In connection with the
770
levels table the following thumbrule can be used to take the current
765
weather situation into consideration:
760
756
751
Barometer display - 1013 = weather dependent deviation
weather dependent deivation + value from levels table = absolute
pressure value
Luft-
druck
A sign is added to the weather dependent deviation. If there is low
(hPa)
pressure the sign is negative and if the pressure is high the sign is
636
positive. This fact should be taken into consideration.
632
628
3. Information from the weather station responsible
624
620
Information on the air pressure for a given level can be attained from the
616
weather station responsible.
612
608
Taking into consideration the pressure difference between the
604
surroundings and the measurement location
600
596
The absolute pressure difference between the location and the
592
measurement location (e.g. flue) can be taken into consideration as
588
described below.
584
580
577
a) Absolute pressure measurement directly at the measurement location
573
and input of the measured value or
569
b) Measurement of the pressure difference between the measurement
565
location and surroundings and correction of the air pressure value
562
determined beforehand by the difference measured while taking the
558
sign into consideration.
554
550
547
543
540
If the measurement location is 800 m above sea level
the value 920 is entered (see Table left)
46
Reference section
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