14. D6 hot-wire thermoanemometer FVAD35
Hot-wire thermoanemometers are especially suitable for measuring low-level air flows
even in cramped and restricted conditions. The primary measuring channels on this
ALMEMO
®
D6 sensor are the real measurable variables - flow, temperature, atmo-
spheric pressure. In the range 0 to +50 °C flow velocity is both temperature-compen-
sated and, by means of a standard atmospheric pressure sensor integrated in the
ALMEMO
®
plug, also pressure-compensated. The overall accuracy of this sensor is
thus outstanding. The measured atmospheric pressure can also be used in the
ALMEMO
®
measuring instrument as reference atmospheric pressure. (see 3.3.1).
14.1 Measuring ranges preset at our factory
Description
Range
Exp Meas. range
Units Resolution
1. Temperature T, t
B-01
DIGI
-1
-20..+70.00 °C
0.1 K
2. Flow, v with PC (TH4)
B-02
DIGI
-3
0.08... 2.000
+
m/s
0.001 m/s
2. Flow, v with PC (TH5)
B-02
DIGI
-2
0.2... 20.00
+
m/s
0.01 m/s
3. Atm. pressure AP, p
B-03
DIGI
-1
300...1100.0 mbar 0.1 mbar
+
Measuring range and resolution depend on sensor type.
The flow velocity of hot-wire thermoanemometers is inversely proportionate to atmo-
spheric pressure (v = v
m
*1013/p
m
); i.e. a 10% deviation (912 mbar) from normal pres-
sure (1013 mbar) already causes a measuring error of 10 percent. The ALMEMO
®
plug on such D6 sensors incorporates as standard therefore an atmospheric pressure
sensor which always and automatically provides the flow with atmospheric pressure
compensation (PC) - even if the channel is deactivated. (see 3.3.1).
14.2 Configuration on a PC via the sensor menu
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