Datasheet

Airflow Sensors AWM40000 Series
Microbridge Mass Airflow/Unamplified and Amplified
76 Honeywell1Sensing and Control11-800-537-6945 USA1F1-815-235-6847 International11-800-737-3360 Canada
FEATURES
1 Manifold mount/o-ring sealed
1 Ceramic flow-tube (non-outgassing),
0-1000 sccm
1 Plastic flow tube, 0-6 SLPM
1 High common mode pressure
(150 psi ceramic flow-tube only)
1 Operating temperature up to 125°C
(unamplified only)
1 High stability at null and full-scale
The AWM40000 Series mass flow sensor
family is based on proven microbridge
technology and includes both amplified
signal conditioned devices and unampli-
fied sensor only devices.
When using the unamplified devices
(AWM42150VH and AWM42300V), the
heater control circuit in Figure 1 and the
sensing bridge supply circuit in Figure 2
are both required for operation per speci-
fication. These two circuits are NOT on
board the sensor and must be supplied in
the application. The differential amplifier
circuitry in Figure 3 may be useful in pro-
viding output gain and/or introducing
voltage offsets to the sensor output (Ref.
Equation 1).
The amplified devices (AWM43300V and
AWM43600V) can be used to increase
output gain and introduce voltage offsets.
The differential instrumentation amplifier
circuitry, heater control circuitry and
sensing bridge supply circuitry are all
provided onboard the amplified sensors.
Figure 1
Heater Control Circuit
Figure 2
Sensing Bridge Supply Circuit
Figure 3
Differential Instrumentation Amplifier Circuit
Equation 1:
V
o
J
2R
2
+R
1
R
4
V
2
-V
1
+V offset
()()()
R
1
R
3
where V offsetJV
S
()
R
6
R
6+
R
5