AWM90000 Series
Mass flow sensor for gases
HEATER CONTROL CIRCUIT
SENSING BRIDGE SUPPLY CIRCUIT
6
10 V
R
a
24.9 kOhm
R
b
24.9 kOhm
A)
1 kOhm
B)
5
7
R
h
3
2
8
Rr
4
1
Note:
Circuits required for operation per specifications. Circuits are not on board the sensor.
A) Customer supplied 1 kOhm resistor (affects temperature compensation and span voltage).
B) Customer supplied 24.9 kOhm matched bridge resistors (affects null output voltage).
Output is measured differentially from pins 8 to 2.
HEATER CONTROL CIRCUIT
(suggested)
DIFFERENTIAL INSTRUMENTATION
AMPLIFIER CIRCUIT (OPTIONAL)
4
2R2 + R
1
R
(
VO =
V2 −V
)
+VOffset
1
R
R3
1
5
R6
R6 + R
where
VOffset =V
S
4/6
December 2007 / 592
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