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.
6, a little ground
A low-level circuit is generally recommended for low-frequency circuits. It has a radial ground wire and a bus-type ground line. Radial grounding is the direct connection of each functional circuit in the circuit with the zero potential reference point: the bus-type grounding is to use a high-quality conductor with a certain cross-sectional area as the grounding busbar, directly connected to the zero potential point, the ground of each functional block in the circuit. Can be connected to the bus. At this time, if multi-point grounding is used, multiple ground loops will be formed in the circuit. When low-frequency signals or pulsed magnetic fields pass through these loops, electromagnetic induction noise will be generated. Due to the different characteristics of each ground loop, the loops are closed in different loops. A potential difference is generated at the point to form an interference. To avoid this, it is best to use a grounding method.
The sensor and measuring device form a complete inspection system, but the two may be far apart. Because the earth current in the industrial site is very complicated, the potential between the two parts of the outer casing is generally different. If the zero potential of the sensor and the measuring device are grounded at two places, that is, two points are grounded, there will be A large current flows through a signal transmission line with a very low internal resistance to cause a voltage drop, causing series mode interference. Therefore, a grounding method should also be used in this case.
