In the field of industrial automation, the electromagnetic compatibility (EMC) of PLC electrical cabinet sheet metal shell is crucial. In order to ensure the stable operation of electrical cabinets in complex electromagnetic environments, its PLC electrical cabinet sheet metal shell has taken many measures in design.
First of all, start with material selection. PLC electrical cabinet sheet metal shell usually adopts metal materials with good conductivity, such as cold-rolled steel plates. The metal material itself can reflect and shield electromagnetic radiation. When the external electromagnetic interference wave hits the shell, the metal shell will reflect most of the electromagnetic waves back, reducing the electromagnetic energy entering the electrical cabinet. At the same time, for the electromagnetic radiation generated inside, the metal shell can also effectively limit its leakage to the outside, thereby preventing interference with other surrounding electronic equipment.
In the design of the connection structure of the shell, the use of continuous metal contact is the key. For example, the cabinet door and the cabinet body are tightly connected by a carefully designed conductive sealing strip. When the cabinet door is closed, the conductive sealing strip can ensure that a continuous conductive path is formed between the door and the cabinet body to prevent electromagnetic leakage. Moreover, at the joints of the cabinet, the conductivity of the entire PLC electrical cabinet sheet metal shell is ensured through precise processing technology and appropriate connection methods, such as riveting and welding, thereby enhancing the electromagnetic shielding effect.
In addition, reasonable opening design is also extremely important for electromagnetic compatibility. Although electrical cabinets require ventilation holes to dissipate heat, the existence of these ventilation holes will become a potential channel for electromagnetic leakage. Therefore, in design, ventilation holes often adopt special shapes and layouts. For example, using honeycomb or circular hole arrays, these shapes of openings can prevent the propagation of electromagnetic interference through the electromagnetic waveguide effect while ensuring the ventilation volume. Moreover, metal mesh can be installed at the ventilation holes to further filter electromagnetic interference. The mesh size and material of the metal mesh are also carefully selected to achieve the best electromagnetic shielding effect.
In addition, in order to avoid electromagnetic interference generated by the internal wiring of the electrical cabinet, a reasonable electromagnetic isolation structure is also designed inside the PLC electrical cabinet sheet metal shell. By setting up metal partitions inside, lines and equipment with different functions are separated to reduce the possibility of electromagnetic coupling. At the same time, when wiring, signal lines and power lines are required to be laid separately and maintain a certain distance to further improve the electromagnetic compatibility of the entire electrical cabinet.
