Measurement Modes in the Main Menu
25
Press the left key to bring up the menu again.
Press the right key to zero the pressure sen-
sor.
NOTE!
The pressure sensor must be zeroed, if the meter
does not indicate V=0 after the tubes have been
removed.
Note
If the air speed reading is not stable or if the
resolution is not high enough, go to the Setup-
menu and select Attenuation > fine (see chapter
6.12)
6.2.2 Theoretical Background
The Wöhler DC 410
FLOW
will calculate the air speed automatically according with the
following formula:
Formula 1
The air density
is determined as follows:
Formula 2
Explanation:
: air speed in m/s
: air density, app. 1.29 kg/m
3
(depends on tem-
perature and air pressure)
: Differential pressure in Pa, measured with the
S-tube
: absolute air pressure, measured with the
DC 410
FLOW
S: Pitot factor 0.93 for S-tube probe
: Measured Temperature
