At present time the improving of technological processes is very important for most of manufacturing companies. As known, the quality performance is impossible without monitoring of defined technological characteristics, particularly, temperature and pressure and others. For example, the values of pressure can characterise the ambience in technological processes of petrochemical industry when chemical processing of natural and synthetic substances. The maintenance of defined pressure level is sufficiently important task when using complicated devices, machines and other technique applied for different research works. Pressure measuring tools in automobile industry are being used in order to sustain the motor operation and safety of other systems. Iit's evident, that the measuring systems are characterised by rather strict requirements to both working characteristics and geometrical sizes and conponents design.
Among leading world producers of measuring devices and pressure contorolling systems in complicated industrial and laboratory equipment one can note TDK (Epcos). High-precision sensors developed by the company allow to get complex data on absolute and gage pressure in settings usable in different fields of application. Produced components are calibrated and have the built-in circuit with thermal compensation. The measurement accuracy is no more than 1%. Main advantages of Epcos sensors: miniature sizes of a case, high accuracy, stability of characteristics, reliability when operating. The absence of expensive materials in sensors and the easy construction allow to produce components with low cost in commercial batches.
The operating principle of Epcos sensors is based on piezoresistive effect. Particularly, mechanical strength appears due to the pressure overfall on different parts of a diaphragm seal. This leads to the sensor resistance changing. Piezoresistors are connected in a Wheatstone bridge and allow to convert tha resistance changing to the electrical signal. The value of this electrical signal is proportional to the value of applied pressure. The ambient pressure impacts on a sensitive element causes its deformation. The temeprature diffrence between surface which is in a contact with ambience and planar side leads to appearance of a heat flow within its volume. Under the impact of pressure and temperature piezoresistors and thermoresistors change its resistance proportionally deformation and temperature difference correspondingly. The changes are being converted in a bridge circuit to the voltage and current signals. After correction these signals are transmitted to the measuring receiver. The application of silica sensor converter allows to increase temporary and temperature stability of devices in comparance with other elements dor pressure measuring. depending on fields of application sensors can be used as a crystall - sensitive element and also as a sensor placed in a hermetic package wich allows to determine the power pressure.
In case when measurements are being conducted in severe conditions and also in water environment it is recommended to avoid the application of chip's front side. These terms are being realized when using the enter of an opposite sensor side for a contact with the measured medium and creation of the field with vacuum on a front side.
Differential Pressure Sensors A pressure difference caused by a higher front side pressure leads to a positive change of the output signal. A higher back side pressure leads to a negative change of the output signal. A differential pressure sensor can be used for flow measurement by measuring the pressure drop across a restrictor.
Gauge Pressure Sensors A gauge pressure sensor is a special case of a differential pressure sensor where either the front or the back side is exposed to ambient pressure.
- Industry:Hydraulic and pneumatic systems; Measurement and control technology; Environmental and climate protection
- Consumer: Barometric measurements in portable electronics; Control of vacuum chambers; HDD
- Automative: Engine management; Exhaust gas treatment; тормозные системы
- В медицине: Braking systems
- Ta-Operating temperature, °C
- U max- Maximum supply voltage, V
- R S- Total bridge resistance, kOhm
- S - Sensitivity, mV/bar. Sensitivity is defined for a bridge voltage supply VDD =5 V
- Pr-Rated pressure, bar
Pressure sensor dies
Pressure sensor dies consist of a piezoresistive silicon element with an anodically bonded glass base. Gauge pressure sensor dies with pressure to front and back side as well as absolute pressure sensor dies with pressure to front side are available. The C29 and C32 pressure sensor dies were developed for absolute pressure measurements in wet media. The difference to conventional absolute pressure sensor dies is the reference pressure chamber which is bonded to the front side and the pressure is applied to the back side.
АК2, АТ2, ASB 1200, T5100 Epcos sensorsare produced on the base of MEMS-technology. As in the case of sensors C27...C33 piezoeffect is been used in this series. AK2 and АТ2 have a strong casing made of steel/plastics and are characterised by improved mechanical properties. output signal is fixed without calibration and thermal compensation. T5100 components for pressure measuring are based on sensors series with monocrystall C33. A signal from a bridge circuit goes to the receiver without calibration and thermal compensation. All goods correspond RoHS.
Full databook on pressure sensors
Полная информация по всем сериям датчиков давления представлена в полном каталоге Epcos.
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