Principle of capacitive displacement sensor

capaNCDT capacitive displacement sensor is based on the principle of plate capacitance. The two ends of the capacitor are the sensor the measured object opposite to it. If there is a stable alternating current through the sensor, the output voltage of the alternating current will be proportional to the distance between the sensor the measured object, so that distance information can be obtained by measuring the change in voltage. The capacitive displacement sensor is a measuring instrument based on the principle of non-contact capacitance. It has non-friction non-destructive characteristics common to general non-contact instruments. It has the characteristics of large signal-to-noise ratio, high sensitivity, small zero drift, wide frequency response. The non-linearity is small, the accuracy stability are good, the anti-electromagnetic interference ability is strong, the operation is convenient.

In practical applications, due to the unique design of the magnetic shielding ring, the German Miyrid capacitive sensor can achieve linear measurement. However, capacitive sensors require that the dielectric constant between the probe the measured object must be consistent. The measurement system is very sensitive to changes in the dielectric within the measurement range. The German Miyridium capacitive displacement sensor can also be used to measure insulators, because these insulators will change the dielectric constant in the measurement gap. By adjusting the subsequent circuit, even if the insulator is measured, an approximately linear signal output can be obtained. Due to the electromagnetic conversion process, capacitive sensors can measure all metals. The impedance value of the measurement system is mainly proportional to the impedance value of the measured object.

Traditional capacitive sensors emit magnetic field lines the side. Magnetic fields can cause errors in measurement results. The German miyrium capacitive sensor has a grounded shielding ring, which can effectively reduce the lateral magnetic field boundary effects, thereby obtaining more accurate measurement results. The magnetic field lines emitted by the ground shielding ring will affect the measurement results.

High precision measurement

The capacitance measurement principle is one of several high-precision measurement principles. But the problem is that such a small measurement distance will cause the same small change in the measurement signal. In other words, only a small amount of electrons between the probe the measured object can be used to show the change in distance. This means that if a small leakage current parasitic current flows through the circuit the probe to the controller, it will also affect the accuracy of the measurement results. Therefore, the cable between the probe the controller requires a special double shielded cable. This special fully enclosed radio frequency cable guarantees high signal quality. The use of double-shielded cables grounded magnetic shielding technology makes high-precision measurements possible.

Due to the change of the ambient temperature, the change of the conductivity of the measured object has no effect on the measurement result. The capacitive measurement principle allows the sensor to be used in environments with fluctuating temperatures. The internal structure of the German miyrium capacitance sensor probe is very complicated. As a flat capacitor, the sensor can be installed on different mechanical structures according to the different requirements of users.

The capacitive sensor of German Miyrid Company is one of the accurate displacement sensors in the world. The resolution can reach nanometer level.

Mi-Iridium's capacitive sensors can be replaced without recalibration. This undoubtedly greatly facilitates customers. This allows capacitance sensors controllers of different ranges to be easily replaced without recalibration. The time to replace the sensor is only a few seconds, which has a huge advantage over most sensors on the market. German Miyridium also allows non-contact grounding of the measured object. If two channels are used for measurement, such as thickness measurement, the measurement results of the two channels must be synchronized. The object under test must be grounded. For capaNCDT series measuring systems, the grounding work is done by the controller. The process is done automatically.

Capacitance measurement principle characteristics:

Using the principle of capacitance measurement, the environment is required to be clean dry, otherwise the change in the dielectric constant between the sensor probe the measured object will affect the measurement result