Pressure sensors vary considerably in their design technology used, performance and application.  Pressure sensors often can be referred to as pressure transducers, pressure transmitters, pressure indicators or pressure switches – are used to measure the pressure of gases and liquids (fluids).

Pressure is an expression of the force and is normally stated in terms of force per unit area. A pressure sensor will generate an electrical signal relating to the pressure imposed. This signal is either analogue or digital in more modern designs, although optical, visual and auditory signals are also common.

Pressure sensors, basics of pressure measurement

Industrial pressure transducers normally have a diaphragm type design that uses strain gauges, which are either bonded to, or diffused into it, with the strain gauges acting as resistive elements. Under the pressure-induced strain, the resistive values change. In capacitive technology, the pressure diaphragm is a single plate of a capacitor that changes its value under pressure-induced displacement. These are probably the most common technologies used in industrial applications for their favourable price/performance ratio.

Pressure is measured against a reference, which greatly depends on the application and installation of the sensor. Depending on the relevant pressure, the term ‘absolute’ is used when the reference is vacuum; ‘gauge’ is used where the reference is atmospheric pressure; and ‘differential’ is used where the sensor has two ports for the measurement of two different pressures.

Pressure sensors are used in a wide variety of applications for control and monitoring purposes. Pressure sensors can also be used to indirectly measure other variables such as liquid or gas flow (in conjunction with an orifice plate), speed, fluid level and also altitude.

Due to the wide range of technologies available, pressure sensors vary considerably in their design, performance, application and cost. Every technology has its own benefits and reasons for selection within an application.

When used directly to measure pressure, applications include meteorology instrumentation, aerospace and defence, research and development, automotive and other machinery or equipment that has pressure functionality implemented. Other applications for pressure sensors include hydraulic and pneumatic systems, water depth, offshore & marine, waste water & sewage, oil & gas exploration, nuclear, medical, food and beverage processing, tank level/contents, HVAC systems, agricultural equipment, environmental monitoring and chemical & processing plants.

Pressure Products Page:  Impress Sensor pressure products page

Basics of pressure measurement is a post from: Impress Sensors

DSK 701C Capacitive Pressure Sensor

A new range of ready-to-mount pressure sensor modules for OEMs is now available that customers can integrate into their machine designs and instrumentation, including equipment that needs to be ATEX-certified for hazardous environments.

The DSK 701C pressure sensor module from Impress Sensors & Systems Ltd is a ready-to-assemble capacitive ceramic pressure sensor module that offers very low pressure ranges (20 bar down to 60mbar) but extremely high overpressure resistance.

An additional benefit to OEMs is that the module is ATEX-prepared for Zone 0: II 1G Ex ia IIC T4 certification. This means the OEM can simply install the sensor module straight into a housing or on a machine, knowing that the module itself will require no additional, separate ATEX certification.

Designed specifically as a cost effective module for OEMs and machine builders, the DSK 701C can also be configured and programmed by the customer via an integrated RS232 interface. An optional configuration kit is available, which enables the OEM to reconfigure sensors for different end user applications. The module is simply connected to a PC via the RS232 interface and menu-driven programming software is used to calibrate pressures, configure starting points and end points of the pressure range, damping and offset adjustment.

The pressure sensor module will have a wide appeal amongst OEMs and specialist machine builders, from waste water, sewerage and marine applications, through to manufacturers of inkjet printers. Some customers may already have their own electronics but require a ready-to-mount, low cost pressure sensor module to complete their system solution.

The DSK 701C has a ceramic membrane and offers a high turn down ratio of 10:1, without sacrificing accuracy. For example, a 1 bar rated sensor module can be turned down to 100mbar, but the accuracy remains at 0.1% and overpressure of 8bar is permissible.

The modules are available in gauge and absolute versions with a 4… 20mA output signal. Response time is 120ms (without electronic damping) and operating temperature range is from –40 deg C to +125 deg C. The unit is supplied with a PTFE filter as standard, with a brass venting tube option also available.

Product Datasheet: DSK 701C Capacitive pressure sensor

Product page: Sensing Element products page

For more information on the DSK 701C, please call the sales department on 0118 981 7980 or visit the website at www.impress-sensors.co.uk

ATEX-prepared Capacitive pressure sensor modules is a post from: Impress Sensors