In addition to the grounding operations of the front-end and back-end equipment, the grounding operation can also select the steel pipe of the transmission line, and perform grounding welding and equipment grounding at the joints and pipe joints. However, the grounding of noise and interference cannot be irregular, and the rules must be followed to achieve the cleaning effect. The first general circuit ground has no potential, and the ground is stable, but there is actually a potential, so you should pay attention to the ground area and the resistance of the ground area. Recommended reading: How to choose the thickness of the LCD splicing screen that suits you?
There are many grounding methods, single point is just one of them. The low frequency circuit uses wires to connect the ground circuit of each unit to a point on the housing, so there is no large loop attack. There is no large loop, no large loop current, no large loop current input and output will be calm. There are many ways to solve it. The method used in detail depends on the structure and function of the system. The concept of "grounding" is that the earth is a common circuit. This is the first grounding problem. In order to solve this problem, there are many successful grounding methods to prevent noise and interference. Methods include the following:
Single-point grounding: Single-point grounding is a method of providing a common potential reference point to many circuits so that signals can be transmitted between different circuits. Single-point grounding requires that each circuit be grounded only once and connected at the same point. Because there is only one reference point, you can be sure that there is no ground loop, so there are no disturbing problems;
Multi-point grounding: The internal circuit of the monitoring equipment uses the shell as the grounding reference point, and the shell grounding of each device is the reference point. The ground structure can provide lower ground impedance. This is because when multiple points are grounded, each grounding wire may be short-circuited; multiple wires can be connected in parallel to reduce the total inductance of the grounding conductor; >>>Recommended reading: "Successful splicing case"
Mixed grounding: Mixed grounding includes single-point grounding and multi-point grounding. For example, the power supply in the system needs to be grounded at a single point, and the RF signal needs multiple ground points. Regarding DC, the capacitor is open, the circuit is grounded at a single point, and regarding RF, the capacitor is conductive, and the circuit is grounded at multiple points.
When many devices connected to each other are bulky (the physical size of the device and the length of the connecting cable are large relative to the wavelength of any existing auxiliary signal), it may interfere with the casing and the cable. When this happens, the path of interference current usually exists in the ground loop of the system. Therefore, it is necessary to pay attention to the following grounding:
Safety grounding: The equipment using AC power supply must be grounded through the yellow-green safety grounding wire. Otherwise, the insulation resistance between the power supply and the internal casing of the device becomes smaller, which may cause electric shock damage;
Lightning protection and grounding: The lightning protection system of the equipment is an independent system, consisting of a lightning rod, a lower conductor and a joint connected to the grounding system;
Electromagnetic compatibility grounding: the grounding required for electromagnetic compatibility planning, including blocking grounding, to avoid interference between circuits due to the presence of parasitic capacitance, and necessary grounding blocking must be carried out;
Filter grounding: Filters usually include signal lines or power lines for grounding bypass capacitors. When the filter is not grounded, these capacitors are in a floating state and there is no bypass effect.
