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Aug 2022
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Copyright © Sensirion AG 2022.
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SFx53xx: for the short body-type (see datasheet) 2 screws are needed for fixation from the bottom side. For the
long body 4 screws can be used from the top. The O-rings must be placed on the manifold side. The design
pictured below is compatible with both “short” and “long” body designs.
7.
Recalibration Tool
Sensirion’s MEMS
-based Mass Flow Controllers are shipped fully calibrated for the gasses specified when ordering. Unlike
traditional, capillary-type Mass Flow Controllers, they do not drift and do not require regular re-calibration.
However, it is also possible to create and save a custom calibration for special use cases. A dedicated tool is available for
this purpose. Possible scenarios, where user re-calibration might be helpful are:
•
calibrate the Mass Flow Controller for gases, for which the controller was not factory calibrated
•
calibrate the Mass Flow Controller at a pressure significantly different than factory calibration conditions (typically
3 bar differential pressure: 4 bar at inlet and atmospheric pressure at outlet)
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any situation which leads to the factory calibration requiring adjustments due to the accuracy requirements, e.g.
vertical instead of horizontal implementation, …
To recalibrate your Mass Flow Controller, you need a source of pressurized gas with defined flow rate and the Sensirion
recalibration software. To precisely measure the flow through the Mass Flow Controller, it is recommended to set up the
Mass Flow Controller in series with a Mass Flow Meter as a reference (see picture). The number of calibration points will
impact the accuracy of the calibration. Generally, fewer points are needed when the new calibration gas has similar
properties (density, thermal conductivity and heat capacity) compared to one of the gasses the mass flow controller has
already been factory calibrated for. An example would be re-calibrating a device for O
2
which has already been factory
calibrated for Air.
The software tool and its manual can be downloaded from the Sensirion website. A link
to “
SFC5xxx/SFM5xxx Viewer
software
” is provided in the “Useful resources”
Figure 3 Suggested manifold design for SFC53xx / SFM53xx
Figure 4 Recommended configuration for re-calibration of Mass Flow Controllers