Background on Differential Pressure Sensors
Measuring the comparative difference between two inputs, differential pressure sensors are a critical part of most mechanical and electromechanical devices that require precise measurement of air, gases or liquids. For example, if there is a valve in a pipe, a differential pressure sensor will measure the pressure on both sides of the valve. If pressures do not match, then it signals that either the valve is not full open or there is a potentially serious issue (such as blockage). Differential pressure sensors are a key element in many devices such as medical ventilators, spirometers, anesthesia devices, industrial flow meters and HVAC systems.
While some variation of differential pressure sensing has existed for hundreds of years, today’s modern pressure sensors can trace their roots back to the late 1960s when Honeywell applied for the first patents in piezoresistive silicon sensor technology. Over the pursuant decades, the technology has been improved by further integrating electrical and mechanical components that are manufactured using silicon processes similar to integrated circuits. This process is known as Microelectomechanical Systems, or MEMS.
Today’s devices, whether it be consumer electronics such as smartphones, medical equipment such as respirators or industrial ventilation systems, have become much more intelligent. But not all components have advanced. Critical to many applications, differential pressure sensors have changed little over the past several decades. This has resulted in product designers having to put together piece-meal solutions that are often not performance optimized and usually extend product development timelines.
The NimbleSenseTM Architecture
Seeing this deficiency, Superior Sensor Technology created an innovative architecture enabling product designers to move beyond this piece-meal approach to a fully integrated module that combines the MEMS sensor with additional circuitry and software. This modular approach is driven by intelligent software that is programmable for each end application. We call this architecture NimbleSense, and it is the industry’s first System in a Sensor. This approach is the same as IC designers have used in designing many of the complex SOCs (System on a Chip) that power today’s smartphones, automobiles, data centers, etc.
Figure 1: System in a Sensor Block Diagram
Using the NimbleSense architecture enables product designers to create highly differentiated advanced pressure sensing systems from a technology toolbox consisting of many building blocks. This methodology greatly improves system performance in the end application, while providing enhanced features and cost-optimized manufacturing solutions.
The NimbleSense architecture combines processing intelligence with signal path integration and proprietary algorithms to enable a much simpler system design and a higher level of sensor performance. Choosing from a wide array of proven and tested building blocks, product designers integrate the appropriate modules to create a differential pressure system optimized for the specific application requirements.
These different modules provide significant design flexibility and greatly speed up time to market. With this System in a Sensor approach, a product designer can quickly and easily develop the pressure sensing solution required in their specific end product. Introduced in the next section, these NimbleSense architecture building blocks enable a 5 to 10x performance improvement as well as a variety of application-specific features.
Technology Building Blocks
Flexibility is at the core of the NimbleSense architecture. This unique technology allows you to quickly prototype and design the sensor into your product, support multiple product lines with one particular sensor, add new capabilities and features via software updates and reduce system cost through lower component count and greater product reliability.
Based heavily on customer feedback, the Superior Sensor Technology engineering team is constantly innovating and introducing new building blocks in the NimbleSense architecture. Here is a listing of the currently available blocks, along with a short explanation of each. In future blog posts, we will go more in-depth on these unique capabilities.
Figure 2: NimbleSense Architecture Building Blocks
- Multi-RangeTM: Multi-range capability allows a single sensor unit to be factory calibrated and performance optimized to support up to 8 different pressure ranges. This feature is beneficial across all our market segments.
- Z-TrackTM: Z-Track employs a proprietary algorithm to virtually eliminate zero drift. Zero error reduction is critical in medical devices such as Spirometers, where an inaccurate reading can have life changing effects.
- Closed Loop Control (CLC): CLC adds capabilities within the module to set and maintain flow rates via pressure management by directly controlling motors, valves and actuators. CLC is of extreme value in medical respiratory devices such as ventilators and CPAP.
- Advanced Digital Filtering: Our advanced digital filtering is optimized for each application to ensure mixed sampling noise is kept well below the noise floor. By removing the mechanical noise, we maximize overall system performance.
- 50/60Hz Notch Filter: Superior Sensors’s notch filter allows designers to easily remove noise at either 50Hz or 60Hz that can impact overall system performance. Commonly used in HVAC applications, our integrated notch filter simplifies system design.
- Self AwareTM: Self Aware sensor technology tracks changes in sensor error levels and generates a notification prior to a system alarm incident. Extremely valuable in devices such as ventilators, Self Aware reduces critical care alarm incidents up to 1000X.