KANOMAX 6501 series Climomaster - Manual (Page 57)

56 Principle of Measurement
About Compensation
This instrument has been calibrated at normal temperature and
pressure. Therefore, if you are going to measure velocity at a
different temperature and pressure, the indicating value will be
affected.
Influence of Measuring Temperature
This instrument has been calibrated at normal temperature.
Because of theoretical fundamentals of hot-wire anemometers, it
can easily be effected by the ambient temperature. To prevent
such influence, temperature compensation is needed. The
temperature compensation sensor senses the ambient, or
surrounding air temperature and forces the velocity sensor to stay
at a constant overheat above the ambient temperature. By
adopting temperature compensation sensors, you can measure air
velocity accurately within a range of 5～60
o C (41～140 o F)
Influence of Pressure at Measuring Point
The instrument is calibrated under atmospheric pressure of 1013
hPa. Since change in the atmospheric pressure will influence the
heat dissipation amount, compensation of the atmospheric pressure
is required. Compensation can be provided by using the following
formula.
Where: Um: Actual Velocity[m/s]
Uc: Indicating Value
Pm: Atmospheric
Pressure at the Measuring Point [hPa]
Measuring Gas Components
This instrument has been calibrated using normal air (i.e. 79%
nitrogen concentration & 21% oxygen concentration). If you wish
to use the instrument in an environment other than normal air, you
will need to compensate for the characteristics of the gas mixture
you’ll be using the instrument in. Please contact your local
Kanomax representative for details.
Uc
Pm
Um
 
1013