Since there are often a large number of electrical and magnetic interference sources at the production site, they can damage the normal operation of sensors, computers and even the entire inspection system. Therefore, anti-jamming technology is an important part of the sensor detection system. For those engaged in automatic inspection work, It is very necessary to understand anti-jamming technology.
A useless signal appearing in the circuit of an electronic measuring device is called noise. When noise affects the normal operation of the circuit, the noise is called interference. The formation of interference during signal transmission must have three factors, namely the interference source, the interference path and the receiving circuit with high sensitivity to noise. Therefore, the method of eliminating or attenuating noise interference can take measures against any of the three items. A more common method in the sensor detection circuit is to take corresponding measures on the interference path and the receiving circuit to eliminate or attenuate the noise interference. The following describes several commonly used and effective anti-interference techniques.
3, electromagnetic shielding
For the high-frequency interference magnetic field, the eddy current principle is used to make the high-frequency interference electromagnetic field generate eddy current in the shielding metal, consume the energy that interferes with the magnetic field, and the eddy current magnetic field cancels the high-frequency interference magnetic field, thereby protecting the protected circuit from the high-frequency electromagnetic field. This shielding method is called electromagnetic shielding. If the electromagnetic shielding layer is grounded, it also has the function of electrostatic shielding. The output cable of the sensor is generally shielded by a copper mesh, which has both electrostatic shielding and electromagnetic shielding. The shielding material must be selected from low-resistance materials with good electrical conductivity, such as copper, aluminum or silver-plated copper.
