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.
2, electrostatic shielding
According to the principle of electromagnetics, there is no electric field line inside the sealed hollow conductor placed in the electrostatic field, and the internal points are equipotential. Using this principle, a metal container with good electrical conductivity such as copper or aluminum is used as a material to form a closed metal container, which is connected to the ground wire, and the circuit value r to be protected is such that the external interference electric field does not affect its internal circuit, and vice versa. The electric field generated by the internal circuit will not affect the external circuit. This method is called electrostatic shielding. For example, in the sensing measurement circuit, a conductor with a gap is inserted between the primary side and the secondary side of the power transformer, and grounding is performed to prevent electrostatic coupling between the two windings. This method belongs to electrostatic shielding.
