Explain the anti-interference problem of injection molding electrical control system
The interference problem of the injection molding machine is mainly divided into two types: internal drying of the injection molding machine and external interference of the injection molding machine.
The internal interference of the injection molding machine is:
1, the signal crosstalk between each other
2. The layout of components is unreasonable and the component quality is poor.
3. Coupling of adjacent loops.
4. The influence of digital ground and analog ground.
5. Parasitic oscillations.
The external interference of the injection molding machine mainly includes:
1. Electromagnetic interference, including the use of electrical equipment near and close to the vicinity of the system, passing vehicles, electromagnetic waves, etc.
2. The influence of power supply fluctuations.
3. Environmental interference, vibration, temperature and humidity, etc.
The internal interference of the injection molding machine is related to the manufacture of the injection molding machine control system, which can be designed and eliminated as much as possible. Imported injection molding machines can do this, and external interference is random, and has nothing to do with the structure. Generally, it is difficult to limit the interference source, and only preventive measures can be taken for specific situations.
The external interference coupling methods of injection molding machines mainly include:
1. Common impedance coupling method. Since the grounding point of the grounding system is different, causing a common impedance, interference of the common impedance coupling is inevitably generated.
2. Electrostatic coupling. That is, the electric field penetrates the interference of the line through the capacitive coupling path.
3. Electromagnetic induction coupling. Since there is a mutual magnetic field between the power line and the signal line, the closed loop in the system generates an induced potential, that is, an interference voltage.
4. Leakage coupling mode: mainly due to the decrease of insulation resistance between adjacent wires or some coupling capacitors, the interference is transmitted to the signal line through the resistance between the conductors.