The poe switch has been out for more than ten years, but many friends are always easy to ignore the poe switch in actual projects. The power supply method chosen by several people still prefers centralized power supply or point-to-point power supply. Of course, there is an advantage of their power supply.
The centralized power supply is connected to the 12V centralized power supply at 220V power supply, and then connected to the camera by 2*1.0 red and black power cables respectively. The 12V power supply distance cannot exceed 100 meters. The current 220V to 12V switching power supply can be adjusted to at most 14V output. According to the line loss and wiring environment, 12V within 100 meters, 13V within 300 meters, and 14V within 500 meters. However, the farther the distance is, the thicker the line is. If it is more than 300 meters, it needs 1.5 square line to ensure stability.
Obviously, centralized power supply has his unique advantages, construction is convenient, easy to maintain, unified control and management, and the transmission distance is far.
Of course, in addition to centralized power supply, we often use a point-to-point power supply mode. This power supply directly draws 220V AC from the monitoring room. Connect a separate DC12V power supply to the camera, then connect it to the surveillance camera and install the bracket.
His advantage is that 220V AC has low voltage loss and strong anti-interference ability during transmission. The disadvantage is that it is more troublesome. Every place needs to be connected to a power supply, which is a bit troublesome to construct.
Here we have to mention poe power supply, many people say that Poe power supply is unstable, then is this really true? There are a few problems in it, which we usually encounter in the project.
Why are engineers not willing to use poe switches?
1. Influenced by the quotation, the poe switch is more expensive than the ordinary switch, and a 16-port poe switch is casually five or six hundred. Most of the projects that we usually contact are small and medium-sized projects. This requires the problem of quotation. The price is high. Party A is not happy. He doesn’t care if you are a POE. If the quotation is low, the cost control will not come down. Not enough money. In contrast to this, it is better to use a common switch, to achieve the same function, and to have a certain profit, and Party A can accept it, and everything seems reasonable.
2, maintenance is troublesome, although the poe switch has been developed for more than ten years, the technology has been relatively mature, but the quality of the wire or poe switch on the market is different, which leads to unstable operation in the PoE power supply process, and the maintenance work in the later stage. The amount is relatively large, or a poe switch supplies power to more than a dozen surveillance cameras. Once the power supply module of the poe switch fails, the monitoring used will stop working.
The wires we usually use are different, and the power supply stability of the wires is high. Even if the wind and solar hybrid power supply system is used, such problems will not occur. Therefore, I will not use the POE switch in consideration of stability. of.
3. Power is limited. There are two standards for popular PoE switches on the market, IEEE802.3af and IEEE802.3at. The IEEE802.3af standard defines a power supply of 15.4W. The IEEE802.3at standard defines a power supply of up to 30W. The power supply of a single port varies depending on the power supply standard. For example, the camera power is 9W, and the af standard PoE switch can be used; if the camera power is 20W, you need to use the standard PoE switch; if the camera power is 30W or more, or the camera and other network devices are large in large projects. Its output power may not keep up.
4, the power supply distance is limited, the current poe stable power supply distance is more than 100 meters, less than 100m in special circumstances, this is a lot of trouble for many projects.
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