Pressure transmitters, also known as pressure transducers, are central elements in measurement, control, and regulation technology. They measure physical pressure in gases or liquids and convert it into a standardized electrical output signal that can be further processed by controllers, displays, or automation systems.
Our pressure transmitters are characterized by high measuring accuracy, long-term stability, and robust design. Depending on the version, they measure relative pressure, differential pressure, or absolute pressure—with selectable signal outputs such as 0–10 V or 4–20 mA. Many models also offer an integrated display (LCD) or can be conveniently configured via DIP switches – without the need for software.
In this guide, we show you what to look for when selecting, using, and installing pressure transmitters. We also explain the differences between the pressure types, provide technical background information, and introduce the different types and accessories.
What is a pressure transmitter?
A pressure transmitter is an electronic measuring device that detects the physical pressure of a medium – whether gas or liquid – and converts it into a standardized electrical signal. This signal can then be processed by control systems, regulators, or monitoring systems to monitor, control, or secure processes.
Unlike simple pressure switches or analog pressure gauges, pressure transmitters provide continuous, precise, and digitally interpretable signals, usually in the range of 0–10 V or 4–20 mA. This makes them ideal for use in automated systems, HVAC systems (heating, ventilation, air conditioning), industrial processes, or in building automation.
Pressure transmitters are often modular in design and, depending on the version, have additional functions such as:
- Integrated LCD display for local pressure display
- Switchable measuring ranges or adjustable signal ranges via DIP switches
- Optional temperature compensation to increase measurement stability under fluctuating ambient conditions
With their ability to measure different types of pressure (relative, differential, or absolute pressure), they can be used flexibly in a wide variety of applications.
How does a pressure transmitter work?
A pressure transmitter – or pressure transmitter – works by sensing mechanical pressure and converting it into an electrical output signal. This conversion process is based on an integrated sensor element that uses different physical principles depending on the design, e.g.:
- Piezoresistive: The pressure deforms a membrane whose resistance changes proportionally to the pressure.
- Capacitive: The pressure changes the distance between two capacitor plates.
- DMS (strain gauges): The expansion caused by pressure deformation is measured via changes in electrical resistance.
The resulting signal is then electronically amplified, linearized, and standardized before being output as an analog output signal (e.g., 0–10 V or 4–20 mA). These signals can then be transmitted over long distances to a central control or display unit without interference.
Many modern pressure transducers also feature:
- Digital configuration options (e.g., DIP switches) for measuring range, signal type, or zero point
- Integrated LCD displays for local visualization of the measured value
- Temperature compensation to ensure reliable measurements even under changing ambient conditions
The function always remains the same: The pressure transmitter delivers a continuous, reliable signal – as the basis for precise process control or system monitoring.
What types of pressure are there?
Not all pressure is the same – and depending on the application, a different type of pressure is measured. It is therefore crucial to know the differences in order to select the right pressure transmitter:
- Relative pressure
- Reference point: Ambient air (atmospheric pressure)
- Description: The pressure is measured relative to the current ambient pressure.
- Typical example: Air pressure in a car tire – it is not specified relative to a vacuum, but relative to the atmosphere.
- Application: HVAC systems, process vessels, fluid systems, heating technology
- Differential pressure
- Reference point: Any two pressure points in the system
- Description: The transmitter measures the difference between two pressure values – e.g., before and after a filter or across a throttle section.
- Typical example: Monitoring the pressure drop across an air filter
- Application: HVAC systems, filter monitoring, volume flow control, laboratory and clean room technology
- Absolute pressure
- Reference point: Absolute vacuum (0 bar)
- Description: The measured pressure is independent of the current ambient pressure.
- Typical example: Weather balloons or applications in vacuum technology
- Application: High-end process technology, research, altitude measurement
The choice of the right pressure transmitter depends largely on the type of pressure required in the respective application. While relative pressure sensors are most commonly used, differential pressure sensors are essential in HVAC and air conditioning technology. Absolute pressure sensors are mainly used in special applications.
For which applications do I need a pressure transmitter?
Pressure transmitters are used wherever pressure conditions need to be reliably monitored and converted into electrical signals. They play a central role in heating, ventilation, and air conditioning (HVAC), e.g., in filter monitoring, volume flow control, or pressure monitoring in air ducts.
In building automation, they help to record operating states and efficiently control ventilation zones. In industrial process technology, they are used to monitor pressure in pipelines, tanks, or cooling circuits. Other areas of application include clean rooms, laboratory areas, refrigeration systems, and water and wastewater systems, where pressure values play a role in safety or quality.
Types of pressure transmitters
Different types of pressure transmitters are available for different requirements and installation situations. Depending on the application, these differ in housing type, output signal, ease of use, and installation position. The following variants offer reliable solutions for HVAC, industry, and building automation:
- Pressure transmitter with high housing: These pressure transmitters are designed for precise differential pressure measurements and are available in several housing variants, depending on the space available and the pipe layout.
| | | | Features: - Different housing orientations (top/bottom) for flexible installation
- Optional LCD for local pressure display
- Configurable via DIP switch
- Ideal for HVAC, clean rooms, building management systems
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- High pressure transmitter 0–10 V / 4–20 mA: This product group offers versatile transmitters with selectable signal outputs and optional display. They are easy to install and configure – even on site.
| | | | Features: - Precise differential pressure measurement
- Robust housing for continuous operation
- LCD display depending on version
- Outputs optionally with 0–10 V or 4–20 mA
- Ideal for air ducts, volume flow measurement, filter monitoring
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- Differential pressure switch: These devices are used for simple, mechanical monitoring of pressure differences. They trigger a switching contact as soon as a specified pressure value is exceeded or fallen below – without any analog output signal.
| | | | - Areas of application: Filter monitoring, air flow, simple HVAC applications
- Advantages: Power-free operation, simple installation, clearly defined switching point
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- Relative pressure transmitter: These pressure transmitters are designed for precise and reliable relative pressure measurement in liquid and gaseous media and are available in two different technologies depending on requirements.
| | | | Features: - Can be ordered with either a ceramic or stainless steel measuring cell
- Optional flexible LCD display
- High accuracy and overpressure safety
- UL and NSF (drinking water) certified
- Ideal for hydraulics, pneumatics, and industrial applications
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- Absolute pressure transmitter: This product group offers versatile transmitters with selectable signal outputs and optional display. They are easy to install and configure – even on site.
| | | | Features: - Output & measuring range selectable via DIP switch.
- Optionally available with flexible LCD display
- Robust IP65 housing
- Ideal for weather measurement technology, ventilation, air conditioning, and control systems
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These types cover the entire spectrum from simple pressure switching functions to professional solutions with display and configurability – suitable for almost any application in the field of pressure measurement.
What factors can influence the service life and performance of a pressure transmitter?
The performance and service life of a pressure transmitter depend largely on the ambient conditions, correct installation, and a suitable application. Severe temperature fluctuations, moisture, dust, or aggressive media can stress the sensor elements and lead to deviations. Mechanical influences such as vibrations and incorrect electrical connections or power supply also have a negative effect. To achieve consistently reliable measurement results, it is important to select the correct measuring range and to check or calibrate the device regularly – especially in sensitive or safety-relevant applications.
Where can I find all the technical data for the pressure transmitters?
All technical data and relevant information about our pressure transmitters can be found directly on the respective product pages or in the corresponding download area. There you can download data sheets, operating instructions, and declarations of conformity—with detailed specifications, installation instructions, and important information for safe use.
What accessories can I use with the pressure transmitters?
A selection of practical accessories is available for our pressure transmitters to facilitate installation and support reliable operation. These include mounting brackets for secure wall or surface mounting, sun protection hoods for outdoor use to protect against direct radiation and overheating, and connection kits that allow differential pressure measurements – e.g., in air ducts – to be implemented easily and in accordance with standards. All accessories are precisely matched to the respective devices and support clean, long-lasting installation.
Frequently asked questions about pressure transmitters
What is the difference between relative, absolute, and differential pressure?
Relative pressure refers to the ambient pressure, absolute pressure refers to a vacuum as a reference, and differential pressure measures the difference between any two pressure points. Depending on the application, a different type of pressure is required.
How accurate is a pressure transmitter?
The accuracy depends on the sensor element used and the measuring range. High-quality transmitters usually deliver very precise measured values that are ideally suited for control and monitoring tasks.
How is a pressure transmitter installed?
Depending on the type, it is installed on a wall, in a control cabinet, or directly in the air duct. For differential pressure measurement, both connection openings must be correctly connected to the system. Mounting brackets or connection sets facilitate professional installation.
Does a pressure transmitter require power?
Yes, pressure transmitters require an external power supply, usually 24 V DC. The exact operating voltage is specified in the respective data sheet.
What does 0–10 V or 4–20 mA output mean?
These values describe the electrical output of the transmitter. 0–10 V is voltage-based, 4–20 mA is current-based. Both variants are standardized and can be easily integrated into control and regulation systems.
Does a pressure transmitter require regular maintenance?
Pressure transmitters are generally low-maintenance. In demanding operating conditions (e.g. heavy contamination, humidity, temperature fluctuations), regular testing or calibration may be advisable.
What accessories are recommended?
Mounting brackets, sun protection, or suitable connection sets are helpful for many applications. They facilitate installation and improve the protection and functionality of the device.
