ASP1400 Bidirectional Differential Pressure Meter
www.sensirion.com Datasheet – April 2008 v2 4/11
1.1 Differential Pressure Characteristics
Figure 2 shows the differential pressure vs. the digital
output of the ASP1400.
Differential pressure applied [Pa]
Figure 2: ASP1400 transfer characteristics.
1.2 Sensor Principle and Gas Types
The ASP1400 device measures differential pressure
indirectly. The sensor effectively uses a calorimetric
method, where fluid motion is converted into thermal
information. A heating resistor on a thermally
insulated membrane is kept above ambient
temperature. In the presence of gas flow, the
temperature distribution up- and downstream is
disturbed. This asymmetry is then measured. Due to
the minimal thermal mass of the membrane,
symmetrical arrangement, and accurate temperature
measurement, the revolutionary specifications of the
ASP1400 devices are achieved.
The above mentioned thermal principle requires
information about the gas type to be measured. The
standard ASP1400 is calibrated for differential
pressure measurements of dry air. Please contact
SENSIRION, if you would like to use the sensor for
applications with other gases.
In Figure 3 the repeatability of the ASP1400 devices
is compared with the repeatability of a typical
differential pressure sensor. It emphasizes the
superior performance of the ASP1400 device.
0.0
0.1
0.2
0.3
0.4
0.5
0 25 50 75 100
Differential Pressure [Pa]
Repeatability [% of measured value]
Repeatability of
typical Differential
Pressure Sensor
Figure 3: Comparison of the repeatability of the
ASP1400 CMOSens
®
sensor with a typical differential
pressure sensor.
1.3 Gas Flow and Pressure Difference
The ASP1400 is calibrated for differential pressure
measurements. However, there is a well defined
relation between pressure drop and mass flow. This
relationship is shown in Figure 4. On request the
ASP1400 can also be calibrated to measure mass
flow instead of differential pressure (for more details
refer to the documentation of the SENSIRION Mass
Flow Meter ASF1430).
-400
-200
0
200
400
-100 -50 0 50 100
Differential pressure [Pa]
Figure 4: Differential Pressure vs. Mass Flow of
ASP1400 device.
1.4 High Precision Differential Pressure
Measurement in Bypass solutions
The ASP1400 differential pressure sensor is
exceptionally well suited in conjunction with customer
specific bypass configurations (see Figure 5).
SENSIRION’s expertise in packaging and flow
measurement combined with the accurate low
differential pressure measurement ability of the
ASP1400, enables the design of novel bypass
solutions over a wide dynamic range.
Figure 5: ASP1400 device using an example bypass
configuration.
