Compensation of Air Velocity Value
13
§ 6
Compensation of Air Velocity Value
Air temperature, humidity and pressure can influence accuracy of air
velocity.
＜
Influence of air temperature
＞
ANEMOMASTER LITE is a hot-wire anemometer that uses heat
radiation to measure wind speed, therefore, temperature
compensation is needed to prevent the influence of ambient
temperature. Without temperature compensation, air temperature
will influence heat radiation and thus will change the readings even
the actual air velocity is the same. The anemometer measures air
temperature at the same time by an inner circuit called temperature
compensation and automatically compensates readings of air
velocity to prevent influence from air temperatures within a range of
10 °C to 40 °C.
＜
Influence of humidity
＞
As air velocity sensor is heated 40 °C to 50 °C above ambient
temperature, it is usually not influenced by relative humidity.
＜
Influence of atmospheric pressure
＞
Change in pressure influences heat radiation. Compensation of
atmospheric pressure is provided by using the formula below.
U
m
: Actual Air Velocity
［
m/s
］
U
c
：
Indicating Value [m/s
］
P
m
：
Atmospheric Pressure at the Measuring Point
［
hPa
］
U
m
＝
P
m
U
c
1013
×
