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During PLC debugging, PLC interference and grounding issues are often encountered. As a technician, having a comprehensive set of conceptual approaches and methods for PLC grounding enables one to analyze and address interference issues in a calm and methodical manner, following one’s own strategy. Currently, there are many articles and methods discussing PLC grounding, but most of them are limited to theory and one-sided experience. If we think from the perspective of drainage pipes in an alternative way, it becomes easy to develop a complete conceptual framework and approach for PLC grounding. I would like to briefly share some of my experiences with you all. The grounding of a PLC is like the drainage pipes in a city, while the static electricity interference is akin to the water within those drainage pipes. To allow water to be drained as quickly as possible, the following steps need to be taken: 1. The diameter of the drainage pipes should be large, so that there is no accumulation of water; just as with grounding electrodes, the diameter of the grounding wires should also be as large as possible. The grounding wire for PLCs should have a cross-sectional area of no less than 2.5 mm2. 2. The drainage pipeline network should have as few junctions as possible, so that water can flow directly into the ground. If there are many junctions in the drainage pipes, the flow of water will be slower; this is similar to the situation with static discharge from grounding electrodes, where interference cannot be eliminated quickly. Therefore, the grounding of all equipment must be connected to the ground through a single point – this is what is known as single-point grounding. As shown in Figures 1 and 2 (the dashed line represents the ground wire). 3. The water level in the drainage network is uneven; there is more water in some areas and less in others. It is best to place the inlet at the area with more water. In this way, the water in the pipe drains faster. The same is true for static electricity; the grounding point should be placed as close as possible to the devices where static electricity is likely to be generated, such as frequency converters and thyristor-based heating devices. As shown in Figure 2. 4. The inner wall of the drainage pipe must be smooth; smoothness reduces resistance, thereby improving the drainage performance. The same is true for the grounding electrode; the grounding resistance must be low, so that the potential difference is small and the interference caused by discharge is reduced. The ground resistance must not be less than 4 ohms. It is easy for an ordinary person to understand why the water in the drainage pipes should be drained as quickly as possible. By thinking about drainage pipes from a different perspective, it becomes easy to adopt a mindset related to PLC grounding; with the right way of thinking, it is simple to deal with PLC interference calmly.