Technical Introduction | Type of pressure sensors

In the industrial sector, pressure is a key parameter that directly impacts process safety, efficiency, and product quality. In multiple industries such as oil refining, chemical plants, food and beverage, and pharmaceuticals, maintaining proper pressure not only prevents accidents but also ensures personnel safety. By monitoring and regulating pressure data, industrial processes such as chemical reactions, thermal energy conversion, and fluid dynamics can be ensured to operate in optimal conditions. Accurate pressure control not only helps save energy and improve production efficiency but also optimizes product quality. For example, in filling operations, accurate pressure control ensures the sealing of containers, preventing leaks and contamination.

Working Principle of Pressure Sensors

Most pressure sensors have a measuring diaphragm inside, which deforms when pressure is applied.

The diaphragm has two sides, one side exposed to the pressure of the medium being measured (such as gas or liquid pressure) and the other side typically exposed to a reference pressure (which can be atmospheric pressure, vacuum, or other known pressures).

When pressure is applied to the measuring diaphragm on the side in contact with the medium being measured, the amount of deformation reflects the difference between the pressure of the medium and the reference pressure.

Types of Pressure Sensors

Pressure sensors can be classified based on the type of pressure they measure, each type having its unique characteristics and application areas:

Gauge Pressure Sensors

Also known as relative pressure sensors, they measure the pressure difference relative to atmospheric pressure. In other words, the reference pressure is atmospheric pressure, so the measured deformation represents the pressure relative to atmospheric pressure (gauge pressure).

Gauge pressure sensors are mainly used in everyday industrial equipment, such as pressure detection in hydraulic stations and pressure control in sintering furnaces.

Absolute Pressure Sensors

These sensors measure the difference between a point pressure and absolute vacuum. Their reference point is absolute vacuum (zero pressure), hence the output pressure value is the absolute pressure.

Since these sensors can measure true pressure unaffected by external influences, they are widely used in fields requiring absolute pressure data, such as meteorological observation, aerospace, and scientific experiments.

Differential Pressure Sensors

When pressure from the medium being measured is applied to one side of the diaphragm, and reference pressure is applied to the other side, the deformation measured is actually the result of the pressure difference between the two sides.

These sensors are often used in air conditioning systems for airflow monitoring, filter status monitoring, and liquid level measurement, helping to optimize and control the operation of these systems.

SENTINEL's Pressure Sensors

Our pressure sensors belong to the gauge pressure sensor category, widely used in industries such as food and beverage, machine tools, and metallurgy. Main products include the S300 series pressure transmitters and SEH series smart pressure sensors.

S300 Series Pressure Transmitters

This series of pressure transmitters is made of stainless steel, compact in size, with a pressure detection range of -1~600bar, and offers two output options: 4~20mA or 0~10V.

SEH Series Pressure Sensors

This series of pressure sensors integrates IO-Link functionality, suitable for modern intelligent industrial needs. They showcase several innovative features:

• Measurement range of -1…600bar, suitable for various industrial applications.


• Large digital display, visible within a 3-meter viewing distance, supporting mirror display for improved convenience and accuracy in data reading.


• New panel with integrated injection molding, resistant to high-pressure water gun spraying.


• 304/316 stainless steel housing, capable of 300° rotation for easy installation.


• Multiple output modes can be set for easy selection.

Application Case

A precision machine tool manufacturer widely uses our SEH series pressure sensors in the hydraulic systems of their equipment. These sensors are used to monitor the pressure of hydraulic oil, ensuring stable performance of the machine tool under high load and high-speed operations. The process data of the sensors are read through the IO-Link function, monitoring the pressure status of the equipment. This significantly improves system reliability and maintenance efficiency. Additionally, the multifunctional output settings allow the sensors to flexibly meet different control needs, simplifying system design and later maintenance.

Customer Support and Services

For more information on general flow, please contact our sales personnel or call the company at 022-83726972. You can also visit SENTINEL's official website at www.sentinel-china.com. The website provides comprehensive product information, selection manuals, CAD and Eplan files, as well as configuration files and tutorials to ensure users can easily access the information they need.

We have a professional technical team ready to provide customized customer support and efficient after-sales service, ensuring the maximum protection of every user's interests.