Classification of FESTO Festo sensors in Germany

Classification of FESTO Festo sensors in Germany

【1】 Pressure sensors are the most commonly used type of sensor in industrial practice, and the pressure sensors we usually use are mainly manufactured using the piezoelectric effect, also known as piezoelectric sensors. We know that crystals are anisotropic, while non crystals are isotropic. Some crystal media produce polarization effects when subjected to mechanical forces along a certain direction and undergo deformation; After the mechanical force is removed, it will return to an uncharged state, that is, when subjected to pressure, some crystals may produce an electric effect, which is called polarization effect. Scientists have developed pressure sensors based on this effect.

【2】 The main piezoelectric materials used in piezoelectric sensors include quartz, potassium sodium tartrate, and dihydrogen phosphate. Among them, quartz (silicon dioxide) is a natural crystal, and the piezoelectric effect is found in this crystal. Within a certain temperature range, the piezoelectric properties always exist, but after the temperature exceeds this range, the piezoelectric properties disappear (this high temperature is called the "Curie point"). Due to the small changes in electric field with the variation of stress (that is, the piezoelectric coefficient is relatively low), quartz is gradually replaced by other piezoelectric crystals. Potassium sodium tartrate has high piezoelectric sensitivity and coefficient, but it can only be applied in environments with low room temperature and humidity. Dihydroammonium phosphate is an artificial crystal that can withstand high temperatures and considerable humidity, so it has been widely used. Nowadays, the piezoelectric effect is also applied to polycrystals, such as piezoelectric ceramics including barium titanate piezoelectric ceramics PZT、 Niobate based piezoelectric ceramics, lead magnesium niobate piezoelectric ceramics, and so on.

The piezoelectric effect is the main working principle of piezoelectric sensors:

Piezoelectric sensors cannot be used for static measurements because the charge generated by external forces is only preserved when the circuit has an infinite input impedance. The actual situation is not like this, so this determines that piezoelectric sensors can only measure dynamic stress.

Characteristics and main applications of piezoelectric sensors:

In the measurement of acceleration, pressure, and force. Piezoelectric accelerometer is a commonly used accelerometer. It has excellent characteristics such as simple structure, small size, light weight, and long service life. Piezoelectric acceleration sensors have been widely used in vibration and impact measurement of aircraft, automobiles, ships, bridges, and buildings, especially in the fields of aviation and aerospace where they hold a special position. Piezoelectric sensors can also be used to measure the combustion pressure and vacuum degree inside the engine.

Piezoelectric sensors are also widely used in biomedical measurements, such as ventricular catheter microphones made of piezoelectric sensors. Because measuring dynamic pressure is so common, the application of piezoelectric sensors is very extensive. In addition to piezoelectric sensors, there are also piezoresistive sensors manufactured using the piezoresistive effect, strain gauges using the strain effect, etc. These different pressure sensors utilize different effects and materials, and can be used in different situations.

Static characteristics of German Festo sensors:

The static characteristics of a sensor refer to the mutual relationship between the output and input of the sensor and the static input signal. Because both the input and output quantities are independent of time at this point, the relationship between them, that is, the static characteristics of the sensor, can be described by an algebraic equation without time variables, or by drawing a characteristic curve with the input quantity as the horizontal axis and the corresponding output quantity as the vertical axis. The main parameters that characterize the static characteristics of sensors include linearity, sensitivity, resolution, and hysteresis.

Dynamic characteristics of Festo sensors in Germany:

The so-called dynamic characteristics refer to the characteristics of the output of a sensor when the input changes. In practical work, the dynamic characteristics of sensors are often represented by their response to certain standard input signals. This is because the response of a sensor to a standard input signal can be easily obtained through experimental methods, and there is a certain relationship between its response to a standard input signal and its response to any input signal. Often, knowing the former can lead to estimating the latter. The commonly used standard input signals include step signals and sine signals, so the dynamic characteristics of sensors are also commonly represented by step response and frequency response.

Linearity of German Festo sensor:

Normally, the actual static characteristic output of sensors is a curve rather than a straight line. In practical work, in order to make the instrument have a uniform scale reading, a fitted straight line is commonly used to approximate the actual characteristic curve, and linearity (non-linear error) is a performance indicator of this approximation degree. There are various methods for selecting a fitting line. If the theoretical straight line connecting the zero input and full-scale output points is used as the fitting straight line; Alternatively, the theoretical line with the smallest sum of squared deviations from each point on the characteristic curve can be used as the fitted line, which is called the least squares fitted line. 、

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