How to select the right pressure sensor?

STS Sensors: Extensive testing is essential in the development of new technology. To achieve reliable results, measurement instruments are required which precisely meet the requirements. We show you which factors play a role here.

Pressure range

An initial indicator in the search for a suitable measurement technology is the pressure range to be measured and whether a measurement of the relative or absolute pressure is anticipated.

Depending upon application, special features have to be considered. Particularly in test and measurement applications, individual measurement ranges are required which standard sensors with ISO pressure ranges cannot deliver. In this case, sensors are needed which display the appropriate pressure range and thus attain the desired precision.

Precision

In engine development for racing cars, the smallest of measured readings are the deciders between victory and defeat on the track. In this case, the utmost in precision is demanded and in specific applications developers will opt for a sensor with ±0.05% FS.

Within this question of precision, the factors of necessity and cost are balanced against one another. The pressure range to be measured is usually a good decision-making aid. If this were extremely broad, then no exceptional precision would be necessary. Those who nevertheless decide for the most precisely available sensors should be aware that this precision comes at a price.

Temperature

The temperature factor in some cases is difficult to determine. Developers are often not exactly aware over which temperature ranges the pressure sensor employed is to deliver its service. Many pressure transmitters from STS , for example, are optimized for operating temperatures from -25°C to 100°C. In this way, the common areas of application are all covered. In principle, all sensors can be optimized and ordered to a special temperature range so that even at temperatures of -40°C or 150°C accurate results can be attained.

Process interfacing

The subject of process interfacing can quickly become an exclusion criterion for developers, since many companies use standardized connections. Even the location where the sensor is to be mounted can be an important factor here.

There are a multitude of optional electrical connections, whether it be M12, DIN, MIL or others, which should also be offered by manufacturers in a variety of lengths and materials.

STS itself provides a broad range of connectors. A multitude of connection options are possible due to the modular construction principle of these measurement instruments.

Output signal

Equally decisive is the question of whether the measured pressure is to be carried as an analog signal or over a digital interface such as Modbus. With an analog signal transmission, the pressure is converted into an analog signal that still needs to be measured. In a digital signal transfer, the value of the measured pressure is directly expressed across an interface.

Space requirements

In various applications, only a little space is available for the mounting of pressure sensors. For this reason, the size of the sensor combined with the available process interfaces can become an important selection criterion. The form of pressure measurement also plays a role here. Piezoresistive pressure sensors are particularly suited to miniaturization. For this reason, STS can offer sensors of only a few millimeters in diameter.

Materials

Where will the sensor be deployed? Which ambient conditions will it encounter? Will it come into contact with steam, gasoline or particular gases? The housing material determines which media the sensor will be exposed to. For applications on the test bench, stainless steel housings are mainly used. Upon contact with saltwater, the material selection shifts to titanium.

A major influence upon the appropriate sensor is also played by the sealant material. The sealing material remains dependent upon the fluid used in the pressure system. Temperatures to be anticipated must also be expressly included during these considerations.

Certifications

When using in particularly dangerous applications, such as the possibility of explosion, certain certifications are essential which supply information about safe operation of the instruments. Within the STS portfolio, there are sensors like the ATM.ECO/IS, which carries the FM, Fmc, IECEx, ATEX certification, whose use is authorized in explosive areas

Delivery period

Long delivery periods can delay prototype testing and ultimately jeopardize product introductions. It should thus be established in advance whether the required sensors are available or what delivery period is to be anticipated for custom production.

The right pressure sensor - Summary

Sensors do not necessarily meet all of the required specifications. In some cases, the required sensor from one manufacturer is not available in the company’s standardized connection option. Considerable additional costs could arise in this case. Delivery periods could also be correspondingly delayed.

To make the choice of the right sensor as easy as possible for customers, our pressure measurement instruments are based on a modular principle. This means that all of our pressure sensors can be calibrated to the required temperature range. Our products are also exceptionally flexible in terms of process interfacing, sealant materials and pressure measurement ranges. Due to the modular construction of our measurement technology, it is possible to deliver pressure sensors to the exact required specifications within the shortest of times.