Fail-Safe Integration with Differential Pressure Sensors
There are times when an application’s undetected failing system part could result in material damage, harm or even death. It is of vital importance that failures in such a system are detected and acted on swiftly by switching off or putting the system into a safe mode.
A good example is a gas burner (water heater, boiler). In a burner, the air-fuel ratio is sometimes controlled by means of a mass air flow sensor, resulting in a pressure-independent system with increased modulation range, better combustion quality and resilience to changes in the system’s air path impedance. A defective sensor could lead to a wrong air-fuel ratio, which ultimately may result in danger to the building’s inhabitants.
A failing component can be detected in different ways. The most obvious way, but often also the most expensive, is to use redundancy of components. A smarter way is to use components that perform self-diagnostics, or which are diagnosed with test patterns by the system's microcontroller. An example of the latter is the SDP620 series sensor, which can be used to measure the mass air flow in Bypass. The SDP620 series sensor – in combination with a predefined testing algorithm run by an external microprocessor – is certified for class C safety level fail-safe operation. Sensirion’s differential pressure sensors have been successfully implemented in safety-critical applications for more than five years.
For more information about our fail-safe certified mass flow and differential pressure sensors or to discuss a tailored solution for your application, please contact our technical experts.
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