Delta HD2114P.0, Operating Manual

Page: 15 / 38

HD2114P/HD2134P
- 15 -
V2.3
The following relationship gives the wind speed: as you can see this is dependent on the three
pressures and the air temperature.
(1)
⎥⎦
⎤
⎢⎣
⎡
•
+
• • • • =
Pv
Ps 100.000
100.000
289
T
B
1000
1.291 C v
K [T]
Pa [Ps] [Pv]
mbar [B]
m/s [v]
° =
= =
=
=
The Pitot tube gives the difference between the pressure present at the front entrance and that
detected from the lateral holes, that is, the dynamic pressure
Pv :
(Ps+Pv) – Ps = Pv
The static pressure Ps represents the pressure difference between the duct internal side in static
conditions and the barometric pressure. This parameter can be set using the "PRES STAT" menu
item (please see the menu description on page 10). The default value is zero and, if not known,
should not be modified.
B represents the barometric pressure present during the measurement: The factory default is
1013mbar. This parameter can be set using the "PRES BARO" menu item (please see the menu
description on page 10).
T is the temperature detected by the thermocouple K present in some Pitot tube models. If the tube
is not fitted with one, an external thermocouple K probe with miniature connector can be attached at
the Pitot tube input. As an alternative, the compensation temperature value can be entered manually
within the -200…+600°C range: please see the °C/°F-ESC key description on page 10.
C is the tube constant. This parameter can be set using the "Cost_PIT_DARC" menu item (please
see the menu description on page 10).
O
PERATION
Connect the Pitot tube outputs (pressure and thermocouple) to the instrument inputs.
The Pitot tube outputs must be connected to the instrument inputs, in agreement with the correct
polarity. The Pitot tube downward output, marked in the figure with the sign (+), must be connected
to the positive connection on the left of the instrument head; the Pitot tube lateral output, marked in
the figure with the sign (-) must be connected to the connection on the right of the instrument head.
Introduce the Pitot tube in the air flow being measured, maintaining the rod at the tube base parallel
to the flow as indicated in the following figure.