Effect Of Pressure On Co Measurement - Vaisala CARBOCAP GMW90 Series User Manual

Chapter 5 _______________________________________________________________ Maintenance
VAISALA ________________________________________________________________________ 65
Effect of Pressure on CO
Ambient pressure affects the CO
pressure differs from the normal pressure 1013 hPa, the transmitter can
correct the reading if you enter the correct pressure value to the
transmitter using an MI70 indicator, computer (ENV command), or using
Modbus protocol.
If you want to apply the pressure compensation in the building control
system instead, multiply the measured CO
compensation multiplier from Table 11.
Table 11 Effect of Elevation on CO
Elevation (m) Elevation (ft)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
Measurement
2
reading of GMW90. If the ambient
2
value using the appropriate
2
Measurement
2
Pressure (hPa)
0 1013
328 1001
656
984
1312
1640
1969
2297
2625
2953
3281
3609
3937
4265
4593
4921
5249
5577
5906
6234
6562
6890
7218
7546
7874
Compensation
Multiplier
1.017
989 1.034
978 1.051
966 1.067
955 1.084
943 1.100
932 1.116
921 1.132
910 1.148
899 1.164
888 1.179
877 1.195
867 1.210
856 1.225
846 1.240
835 1.255
825 1.269
815 1.284
805 1.298
795 1.312
785 1.326
775 1.340
766 1.354
756 1.368
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