Differential pressure transmitter

PREMASGARD® differential pressure sensors are used to measure positive pressure, negative pressure and differential pressure in almost neutral gaseous and liquid media. Measured variables are converted into a standard signal of 0-10 V or 4...20 mA. Areas of application include industrial or sanitary measurement technology, hydraulic systems and building automation.

Guide to differential pressure transducers

Guide to differential pressure transmitters

The differential pressure changes due to air flows, filter contamination, damper positions or pressure conditions in ventilation and air conditioning systems. Even small deviations can impair the efficiency of a system - for example due to clogged filters, incorrectly set volume flows or undetected leaks.
Differential pressure sensors help to detect such changes at an early stage. This allows maintenance requirements, energy losses or faults in the air flow to be specifically identified. The sensors provide reliable data for your HVAC, building or automation systems and thus actively contribute to operational safety, energy efficiency and system optimization.

Content

Types of pressure measurement Functionality of a differential pressure transmitter Areas of application for differential pressure sensors Advantages of modern differential pressure transducers The right choice of differential pressure sensor Differential pressure sensors from S+S

What is a differential pressure transducer?

A differential pressure sensor measures the pressure difference between two points in a closed system, for example on flow and return lines in hydraulic circuits.
The measuring principle is based on comparing the pressure values on the "high side" (P1) and the "low side" (P2).
The measured differential pressure is calculated from the difference Δp=P1-P2Δp = P1 - P2Δp=P1-P2.
This measured value is then converted into an electrical signal - for example 0-10 V, 4-20 mA or Modbus RTU - and can be passed on to building management systems, controllers or control systems.

Types of pressure measurement

Differential pressure
Measures the pressure difference between two measuring points (e.g. upstream and downstream of a filter, pump or valve) - suitable for closed liquid or gas systems in which the pressure difference provides direct information about the filter condition, flow rate or flow resistance.
Relative Pressure
Here the Pressure is measured in relation to the ambient pressure. The sensor compares the process pressure with the atmospheric Pressure - Ideal for monitoring overpressure or underpressure in open tanks and pipes.
Absolute Pressure
Here the measurement is made in relation to a vacuum (P0). This measurement is mainly used in industrial processes, laboratories and special applications where exact absolute values are required.

Functionality of a differential pressure transmitter

1st pressure sensor element

A pressure-sensitive diaphragm or a piezoresistive sensor registers the pressure difference between two points. The diaphragm is made of corrosion-resistant materials that allow contact with water, oils or neutral gases. The minimal deformation (caused by the pressure difference) is converted into an electrical signal.
2. signal processing

The sensor signal is electronically processed, filtered and linearized.
This results in a stable, low-noise measured value - even under changing ambient conditions.
3. output signal

As standard, the devices provide an analog output signal of 0-10 V or 4-20 mA. This means they can be easily integrated into standard building management systems, PLCs or process control systems.
4. extension with LCD-SHD module

The optional S+S LCD SHD display module can also be used to convert the analog 0-10 V signal into a digital Modbus RTU protocol. This turns a conventional transducer into a fully-fledged signal converter with a digital interface - ideal for networked applications.
5. calibration and temperature compensation

To ensure maximum accuracy, the devices are calibrated and temperature-compensated at the factory. This ensures that the measurement stability remains constant over a long period of time.

Typical areas of application for differential pressure sensors

Monitoring of filters and flow resistances in water or oil pipes
Differential pressure measurement in pump and hydraulic circuits
Process control and flow monitoring in closed systems
Cooling water or heat exchanger systems in industrial environments
Filter monitoring in neutral gas lines

The precise detection of the smallest pressure changes enables early maintenance and prevents energy losses due to clogged filters or uneven flow conditions.

Advantages of modern differential pressure transducers

Modern differential pressure sensors offer numerous advantages that make them an indispensable component in the precise measurement of pressure. Pressuremonitoring of liquid and gas systems.
They combine high measuring accuracy with mechanical robustness and ensure stable results even at high operating pressures and changing process conditions.

Thanks to modern sensor technology and temperature-compensated electronics, these devices provide reliable, repeatable measured values over a long period of time.

Integration into existing systems is simple thanks to standardized analogue signals - typically 0-10 V or 4-20 mA. If required, the transducers can also be integrated into digital communication systems such as Modbus RTU using suitable signal converters or display modules.

Further advantages of modern differential pressure transmitters

Large selection of measuring ranges - from low to high pressure levels (e.g. 0.1 to 40 bar)
Corrosion-resistant materials for use in water, oil or gas environments
Long-term stable and temperature-compensated sensor technology for precise results under changing conditions
Low-maintenance design thanks to robust sensor housing and durable measuring cells
Flexible signal options for integration into analog or digital control systems

Precise differential pressure measurement is a key element of energy-efficient HVAC systems. By precisely recording the actual air flow and pressure curve in the system, it enables the fans to be controlled according to demand. As a result, they only operate when air is actually required, which significantly reduces power consumption. At the same time, the filter load is continuously monitored and detected at an early stage.

A differential pressure transducer can be used in both air and water filtration systems to precisely determine whether a filter is still permeable or should already be replaced. If the measured differential pressure rises, this indicates that the filter is becoming increasingly dirty or clogged - maintenance or replacement is required. This not only prevents unnecessary energy losses due to clogged filters, but also increases system availability and operational reliability.

The control of temperature and air quality also benefits from this precise measurement - constant pressure conditions ensure stable, hygienic conditions indoors and a pleasant indoor climate.
The differential pressure sensor thus makes a decisive contribution to avoiding energy losses, optimizing maintenance work and sustainably improving the overall performance of the building automation system.

The right choice of differential pressure sensor

The selection of the right differential pressure sensor depends heavily on the application. Different requirements are relevant for liquids than for air systems: materials, seals and pressure ranges must be precisely matched to the medium in order to avoid measurement errors or corrosion.
When selecting a sensor, you should consider the following criteria, among others:

Measuring range: Depending on application (e.g. 0-100 Pa for air ducts, up to 40 bar for liquids)
Medium: air, water, gas or oil
Output signal: Analog (0-10 V, 4-20 mA) or digital (Modbus RTU)
Mounting type: Wall mounting, control panel or direct pipe connection
Protection class e.g. IP54, IP65 or higher for demanding environments

Tip: S+S Regeltechnik offers a variety of models with different measuring ranges, signal types and housing variants to meet your exact requirements.

Differential pressure sensors from S+S Regeltechnik - Quality "Made in Germany"

For more than 20 years S+S Regeltechnik for innovative and reliable measurement technology from Germany. Our differential pressure transmitters are specially developed for use in HVAC systems and building automation and offer:

Precise differential pressure measurement at high system pressures
Short response times
High interference immunity
Stable signal output over many years
Optionally expandable with LCD-SHD module for Modbus communication

All devices are calibrated and tested in the factory and meet the highest quality standards.

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Differential pressure transmitter