How Does a Pressure Sensor Work?
A diaphragm or sensor cell deforms under the influence of pressure. This deformation is measured using a piezoresistive bridge, a capacitive element, or an inductive system. The built-in electronics compensate for temperature effects and linearise the signal. The result is a stable output signal: 4–20 mA, 0–10 V, or a digital protocol such as IO-Link or HART. Your control system reads this signal for monitoring, logging, or control purposes. This produces a reproducible measurement, even under varying process conditions.
Which Types of Pressure Sensors Are Available?
The choice of the right type depends on your reference point and process conditions:
- Gauge pressure sensor – measures overpressure relative to atmospheric pressure. Used in pipeline pressure measurements and compressed air installations.
- Absolute pressure sensor – measures pressure relative to a vacuum reference. Suitable for vacuum applications and barometric measurements.
- Differential pressure sensor – measures the pressure difference between two points, for example across a filter or orifice. Used to determine flow rate or detect contamination.
- Vacuum pressure sensor – detects pressures below atmospheric pressure. Applied in vacuum grippers, packaging machines, and laboratories.
Choose a gauge pressure sensor for pipeline pressure, a differential pressure sensor for filter monitoring, and an absolute pressure sensor for vacuum or resistance tests.
Pressure Sensor for Water or Air – What Are the Differences?
The medium determines which version you need. Water places different demands on sealing and material than compressed air or vacuum.
| Application |
Requirements |
Recommended version |
Supplier |
| Water / process industry |
Wide measuring ranges, robust housing |
Gauge or absolute pressure sensor |
Wika, IFM |
| Hygienic design (food, pharma) |
CIP/SIP resistant, smooth surfaces, EHEDG compliant |
Hygienic pressure sensor |
Hengesbach |
| Compressed air / pneumatics |
Fast signal transmission, compact design |
Silicon cell sensor |
Festo |
| Vacuum |
Detection below atmospheric pressure |
Vacuum pressure sensor with negative measuring range |
Wika, IFM |
For analogue readings only, without an electrical output signal, view our instrumentation range. For process integration and automation, choose a pressure sensor with a 4–20 mA or IO-Link interface.
Pressure Sensor Applications by Sector
Process industry (chemical, pharmaceutical, food & beverage)
Monitoring pressure in pipelines and reactors to guarantee product quality and safety. For hygienic applications such as food & beverage and pharmaceuticals, Hengesbach supplies pressure sensors with hygienic design – CIP/SIP resistant and EHEDG compliant. For general process industry, Wika and IFM are the appropriate choice. Combined with flow meters and level meters, you create a complete measurement system.
Water and wastewater management
Measuring water pressure in pump systems and pipelines to prevent pipe failure and monitor filtration processes. Wika supplies robust versions with wide measuring ranges. Leak detection is a logical addition here.
Compressed air and pneumatics
For monitoring compressed air pressure in production lines and pneumatic systems, Festo pressure sensors are applied, with direct IO-Link integration and measuring ranges starting from 0–0.05 bar.
Machine safety and hydraulics
Protection of hydraulic systems against overpressure and monitoring of stable machine and drive operation. IFM and Wika offer versions with switching outputs and IO-Link for this purpose.
Medical gases and laboratories
Accurate monitoring of oxygen, nitrogen, or vacuum to ensure reliable test results and patient safety.
When Should You Choose a Digital Pressure Sensor?
You choose a digital pressure sensor when accurate logging, remote parameterisation, or communication via bus protocols is required. Digital versions with IO-Link or HART offer local displays, switching outputs, and diagnostics – useful during commissioning and maintenance. They are less susceptible to noise and long cable runs than analogue variants. For integration into MES or SCADA systems, or for remote monitoring, digital is the recommended choice. Analogue variants (4–20 mA or 0–10 V) are sufficient for straightforward process control without network requirements.
Select the right pressure sensor based on medium, measuring range, and interface – or request advice directly from our instrumentation specialists.
Frequently Asked Questions
What is the difference between a gauge and an absolute pressure sensor?
A gauge pressure sensor measures overpressure relative to ambient air. An absolute pressure sensor uses an internal vacuum as a reference and measures independently of atmospheric pressure. Choose absolute for vacuum or altitude applications, gauge for pipeline pressure and compressed air.
How do I select the correct measuring range for my pressure sensor?
The measuring range should be at least 10–20% greater than the maximum process pressure. In the case of pressure fluctuations or pulsations, choose a range with sufficient margin to avoid overloading the sensor. Unsure about the right range? Our specialists will advise you based on your process specifications.
When should I choose a differential pressure sensor instead of a standard pressure sensor?
Choose a differential pressure sensor when you want to measure the pressure drop across a component, such as a filter, heat exchanger, or orifice. The pressure difference between inlet and outlet provides information about flow rate or degree of contamination. For straightforward pressure monitoring in a single pipeline, a standard gauge pressure sensor is sufficient.
