Spirometry Pressure Sensors

Z-Track Eliminates Zero Drift

Spirometry – Lung Function Testing

Utilized in the diagnosis and management of various lung diseases, the spirometer is an essential instrument in pulmonary medicine. To accurately determine a patient’s lung functions, the spirometry product relies on high-performance differential pressure sensors. Additionally, these handheld units must provide highly accurate readings regardless of how the unit is positioned when held. Additional measurements are typically required to ensure accurate results due to unstable sensor zero functionality. Spirometry measures lung capacity and volume under various test conditions. Some of the most common measurements:

  • Forced Vital Capacity (FVC) – largest amount of air that you can blow out after taking your biggest breath
  • Forced Expiratory Volume (FEV1) – amount of air you can blow out in the first second of exhalation.
  • PEF (Peak Expiratory Flow), MVV (Maximum Voluntary Ventilation), TLC (Total Lung Capacity), and other measurements.

For example, the value of FVC together with FEV1 can help diagnose the type of lung disease present. 

A low FEV1 value indicates that there is a blockage in the air flow out of the lungs – a critical item to be monitored for COPD (chronic obstructive pulmonary disease). Spirometry is thought to be the most reliable way to test your lungs for COPD and asthma. Additionally, Spirometry testing determines the severity of the disease and is done to cross-check the efficacy of a given lung treatment. 

SP Series Differential Pressure Sensors

Superior Sensor Technology has optimized the SP Series of differential pressure sensors for spirometry and FOT (forced oscillation technique). This product family addresses the performance requirements with a highly unique and differentiated offering: 

  • Improved auto-zero performance using the proprietary Z-TrackTM algorithm to maintain minimal zero point deviation – Virtually eliminating the impact of zero drift.
  • Positionally insensitive devices – Maintaining consistent and highly accurate handheld readings regardless of the physical orientation of the spirometer.
  • Sensor accuracy, total error band, and short-term zero stability are the best in class – ensuring consistently precise Spirometry measurements, yielding faster and more accurate patient diagnosis.
  • Warm-up time is essentially eliminated – An excellent choice for time-critical applications.
  • Low power consumption – compatible with leading handheld requirements.
SP Series product matrix

SP Series – Differential Pressure Sensors with Z-Track

SP Series


  • Highly integrated dual sensors with ADC and DSP
  • Selectable pressure ranges from ±250 Pa to ±40 kPa
  • Z-Track virtually eliminates zero drift
  • Ultra low noise, 19-bit effective resolution
  • Very high accuracy ±0.1% of the selected range
  • Long-term stability ±0.1% of FSS in the first year
  • Output update rate of 500Hz
  • Selectable bandwidth filter from 25Hz to 250Hz
  • Temperature-compensated from 0°C to 50°C
  • Supply voltage compensation
  • Fully integrated compensation math
  • Standard I2C and SPI interfaces

Engineering Design Resources

CAD Design Files

3D Model & Configurator: SP Series

Select product requirements from the table to see the order part number. You can also view and download 3D Models in native CAD format.

(model download requires registration at CADENAS PARTsolutions)

90° Port Adapters

Depending on your product design, you may need the ports facing to the sides instead of the top. Superior offers highly reliable, high-quality adapters that plug into the two ports of our pressure sensors for easy implementation. With these 90° adapters, there is no need to worry about z-height.

90° adapters are available with and without o-rings:

KP-RAR: without o-rings

KP-ROR: with o-rings

Adapters are offered in packages of 50 and 1000.

Recommended NimbleSense Features for SP Series

A single device can accommodate up to eight different pressure ranges (from 250 Pa to 40 kPa across the SP Series), with each range being factory-calibrated and optimized to maintain consistent total error band, accuracy, and stability. This alleviates the complexity and complications associated with working with multiple sensors. Utilizing a Multi-Range part streamlines both the design and manufacturing process, eliminating the need for researching, purchasing, and integrating numerous parts.

Implementing the same component in all designs enhances efficiency and ease, and pressure adjustments are conveniently controlled through a single software command. Moreover, Multi-Range provides the added benefit of a singular inventory item, adding value and convenience to manufacturing operations. In summary, the value of Multi-Range is apparent to both design and manufacturing teams alike.

SP160 Multi-Range Comparison

Benefits of Multi-Range Technology include:

  1. Design flexibility with the ability to adjust pressure range throughout the development cycle
  2. Simplified product design with one sensor replacing up to 8 different sensors
  3. Ability to quickly develop product variants at different pressure ranges without changing hardware design
  4. Greater economies of scale by purchasing larger quantities of the same product
  5. Reduced manufacturing complexity and costs due to simplified calibration of sensors
  6. Up to 4x reduction in sensor inventory costs and product obsolescence
  7. Allows manufacturers to build fewer product variants, significantly lowering working capital requirements and inventory

To ensure precise and reliable medical readings, the company has developed its proprietary Z-Track technology that eliminates zero drift, which is crucial for accurate readings in medical devices like Spirometers. Z-Track enhances the accuracy of spirometers, resulting in more effective diagnoses and better treatment plans.

This technology maintains minimal zero-point deviation irrespective of the elapsed time, and combined with the Superior’s position insensitivity capability, the company’s pressure sensors offer the most accurate readings for all types of spirometry equipment. Users can rely on Z-Track technology for virtually error-free readings, regardless of the spirometer’s positioning or use. By employing Z-Track, we not only eradicate zero errors, but also guarantee that all readings are precise, reliable, and valuable for informed medical decisions.

Z-Track Graph

Benefits of Z-Track Technology include:

  1. Eliminate zero errors to ensure the most accurate spirometer readings in the industry
  2. Consistent performance regardless of elapsed time
  3. Extremely fast data transfer rate
  4. More effective medical diagnoses and treatment plans

Video Corner

SP Series Benefits Video

Z-Track Technology Video