How to choose the monitoring system power supply and its installation method?

The power supply of the camera in the video surveillance system is the power supply that ensures the normal and reliable operation of the monitoring device. How to reasonably arrange the power supply installation and power line selection of the monitoring system ?

The camera's power setting is based on whether the camera is on the side of the control host or a relatively long distance. If it is relatively close, a high-power DC power supply is directly installed next to the host, and multiple cameras are connected to this power supply. The power of the DC power supply More than the sum of the power of the camera is enough. It should be used for long distances assigned to 220V AC power and then the edge of the camera by the camera power supply to the power transformer, 220V AC power line from the video line should be greater than 30 cm, to avoid magnetic interference, image transfer quality.

Power selection

Working current is about 200~300mA 500mA-1A power supply integrated camera can be selected ; working current is about 350 ~ 400mA can choose 1A power infrared camera; small medium operating current is 600-700MA can choose 1A power supply; large infrared Camera operating current 1000MA-1200MA can choose 2A power supply. Power supply In a monitoring system, the cameras can be powered individually or in multiple centralized power supplies. If multiple cameras are centralized to supply power, the current required is the sum of multiple camera currents.

Suppose a monitoring system for a dome camera 10 a common uniform supply, because the current is a hemisphere 300-400MA, camera 10 so that the current is 3000MA-4000MA, should choose a power supply 5A or 6A.

The selection of monitoring system power line wire diameter: Assume that the four cameras have a monitoring distance of less than 40 meters : Each camera can be individually wired with RVV2 x 0.5 power cable to the monitoring host and powered by a small switching power supply. If 4 hemispheres or bolts are used, 2 can be selected 12V1A 12V2A power supply or a power supply, by way of the camera 4 to take parallel electrical, wire saving comparison, if a larger number of cameras, eight cameras, should be used in high-power centralized power supply 12V DC power supply At this time, because the current is too large, the voltage drop on the power line must be considered. Under normal circumstances, the system of 8 cameras, the longest distance does not exceed 40 meters , can be RVV2*0.75 wire centralized power supply, if the 16- way System centralized power supply, we must choose RVV2 * 1.0 power cord.

The above describes the selection of the power cable from the camera to the surveillance host at a distance of no more than 40 meters . If the distance from the camera to the host exceeds 40 meters , it is necessary to consider using the 220V centralized power supply, and transform the camera to 12V to power the camera. Under normal circumstances, 220V power supply, as long as the system is not too large, 8 below, within 200 meters of the distance, you can choose RVV2 * 0.5 of the wire, if the 8 above, are high-power infrared cameras, we must consider The RVV2*0.75 power cable is supplied. In addition, if the distance is further, it is better to use RVV2*1.0 wire to ensure safety .

Power selection method

1. Use twisted pair power supply

Category 5 or more unshielded twisted pair cables are used as power supply cables for surveillance cameras . This simplifies cabling , but you must ensure that the transmitted power meets the requirements of the equipment. If the equipment power supply is 10-12VDC , the current is 500MA , and the internal resistance of the twisted pair is 10 Ω / 100 meters ( measured for actual use ) . If the transmitted power is 12VDC , consider the distance voltage attenuation and ensure the normal use of the equipment. The transmission power is within 150 meters .

2. Independent RVV power supply

According to the power of the terminal camera, the general fixed bolt power does not exceed 10W , the infrared bolt gun generally does not exceed 20W , the ball machine is about 35W . In terms of power alone, the RVV2*0.5 line is sufficient, and the national standard 0.5 line can carry approximately 1 KW of load. At long distances, considering the attenuation, it is recommended to use a line of not less than 1.0 . If the number of cameras is small ( less than five ) and the distance between the camera and the monitoring host is relatively short ( less than 50 meters ) , each camera can be independently equipped with RVV2 x 0.5 power cables to the monitoring room and powered by a small transformer. If the number of cameras is large, a 12V DC power supply with high power should be used to provide centralized power. During the process, all the camera's total power and the voltage drop formed by the transmission line must be taken into account (the “line loss”, the resistance of a 1 m2 copper wire is 1.8 Ω per 100 m ) . For the monitoring of a building, the construction of a double plastic generally by a copper wire 2 2.5-6m2 as a power source to the main control room by the lead line well, and the well down along the floor of each camera to the line well. On the floor of each camera power supply, which may be a primer layer well line RVV2 × 1 or RVV2 × 1.5 (if the number of cameras beyond six layers) power line power to the camera, or every lead sheathed cable with RVV2 × 0.5 Corresponding power supply.

Resistance formula: R=p*L/sp is the resistivity unit in milliohms, L unit meters, s units square meter

The resistance of a copper wire with a size of 1 m2 is 1.75 Ω per 100 m R = 0.0175 × 100/1 = 1.75 Ω

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.