KELLER PRESSURE - Your Swiss pressure sensing specialist

The differential pressure transmitters of the PD-39X series measure the pressure difference indirectly using two absolute pressure sensors. The dual-sensor design with numerical differential formation also outputs the line pressure values via the digital RS485 interface and guarantees a high overload resistance. The additional analog current or voltage output is primarily used to output the differential pressure range, which is freely rangeable within the line pressure range.

The differential pressure transmitters of the PRD-33X series are designed for accurate measurements in low pressure ranges with very high overload on both sides. In addition to the differential pressure sensor, which may only be exposed to gases at its rear face, the devices have an additional absolute pressure sensor that measures the line pressure. Both measured values are output via the digital RS485 interface and are the ideal basis for cryogenic tank monitoring.

The capacitive pressure transmitters of the PD-41X series are designed for measuring differential pressure values in the mbar and µbar range. They use digital compensation with a mathematical model to achieve an accuracy of 0,1 %FS – in the temperature range from 10 to 40 °C, this value even corresponds to the total error band. In addition to the digital RS485 interface, the X-line transmitters have a rangeable analog current or voltage output.

The differential pressure transmitters of the PD-23 series are designed for industrial applications and are supplied with a G1/4 internal thread as standard. They are based on a fully analog circuit. The PD-23 transmitters have a single silicon diaphragm in their interior, which is pressurised from both sides and measures the pressure difference directly. This design enables them to measure tiny pressure differences even at an extremely high line pressure.

The pressure transmitters of the 22M series with brass housing were designed to be a reliable solution for automotive and industrial applications. They are homologated and can be used, for instance, to measure the content of the gas tank in bivalent vehicles.

The 22DT series has been specially developed for use in bivalent vehicles (volume flow measurement when running on natural gas) and is homologated for the automotive industry. However, it also has other industrial applications. The NTC or PT temperature sensor located directly beneath the steel diaphragm reacts more quickly to temperature changes thanks to its special design. The pressure transmitters are protected against electromagnetic fields up to 200 V/m and output the measured values as a ratiometric 0,5...4,5V analog signal. The connections of the temperature sensor are fed out directly.

The highly dynamic and compact 21PHB pressure transmitter is suitable for use in liquids and gases, and can process pressure changes with a bandwidth of 20 kHz. This is achieved by means of the continuous analog signal that is adjusted by a digital circuit in real time and is amplified to a standardised 0...10V signal. The miniature sensor head with a fine M6 thread can withstand temperatures of up to 100 °C and is overload-proof up to a magnitude of four times the measuring range.

The pressure transmitters of the 22S series were designed for use in automotive and industrial applications. They are homologated and every one of their elements has been configured for optimum reliability. In this steel version of the 22 series, all parts that come into contact with media are made of stainless steel (AISI 316L).

The programmable pressure switches of the 22-PS series are encased in a compact yet robust steel housing and are available with PNP or NPN wiring. The pressure switches can be supplied pre-configured at the customer's request. With the aid of the dV22-PP programming unit (available for purchase separately), the two switch outputs can be programmed at any time to be normally closed or normally open at a range of switching points with a window or hysteresis function.

The pressure transmitters of the 23SY-Ei series are designed for elevated requirements in industrial applications. Thanks to its modular concept, this series is highly flexible and makes it possible to realise customer-specific requirements in very little time. The sophisticated compensation circuit makes it possible to specify a narrow total error band. Intrinsically safe – suitable for use in explosive atmospheres.