Monitoring system centralized power supply calculation method

The calculation of monitoring centralized power supply has been asked by many friends. Although the monitoring commonly used has independent power supply mode, centralized power supply mode, and POE power supply mode, we have mentioned centralized power supply many times before, and the introduction of independent power supply is less. Everyone has encountered such problems, so let's take a look at this issue.

First, how to properly configure the camera power supply of the entire monitoring system?

This problem often makes it difficult for many friends who have just been monitoring the business. Many of the solutions have found that the power supply capacity of the original design was not enough, and additional equipment was needed, causing the phenomenon of squashing with the party. In fact, because the camera starts at a moment, the starting current is very large, and the loss of long-distance transmission in engineering, the power required by the surveillance camera is not simply added to the rated power of all cameras.

The correct approach is to add the power of the camera of the entire monitoring system and multiply by 1.3 times. This is the actual power required by the camera, and then add about 30% of the loss; finally, add 30% of the margin, as Expansion will be used in the future.

for example:

If there is a fixed gun camera in a commercial building, and the rated power of each surveillance camera is 4W, how do we configure the camera power supply?

According to the above calculation method, we calculated that the rated power of the camera is 4W*100 units=400W. The actual power used by the camera is 400W*1.3=520W. After considering the loss, the power required by the camera is 520W*1.3=676W plus the power supply. Quantity, the final power required to configure the camera is 676W*1.3=878W

Summarized as follows:

The power supply that the camera needs to be configured = the rated power of the camera *1.3*1.3*1.3 (Note: If the monitoring distance is extremely long, it is necessary to increase the power supply appropriately and increase the power supply voltage).

Second, the configuration of the surveillance camera power supply, what is the most taboo?

The most taboo is that the entire monitoring system shares a power supply. The reasons are as follows:

1. When the system is being repaired, it is often necessary to turn the power on and off. All the cameras are started at the same time when the power is turned on. The starting current is particularly large, and the impact on the power supply is very large, and the power will be burned seriously.

2. All surveillance cameras share a single power supply. When the power supply fails, the entire closed-circuit monitoring system is paralyzed. In particular, some important entrance and exit images cannot be monitored, which may cause unnecessary trouble. So what should be the right approach? As the above example, a commercial building has 100 fixed cameras, which require a total of about 800W of power. The correct configuration should be 4, each 200W power supply. In this way, when a power supply fails, the camera of the important entrance and exit can be connected to other good power supplies without affecting the operation of the entire system.

Third, the monitoring camera power supply needs to pay attention to what problems?

First: When connecting the camera to the power supply in the centralized power supply scheme, do not connect the camera with a far distance to the surveillance camera with a close distance to the same power supply. If connected to the same power supply, the power supply voltage is high, the camera will be burned at a close distance, the power supply voltage is low, and the camera with a long distance has no image.

Second: If the monitoring distance is too far, you need to configure a higher voltage power supply, such as 30V, 36V, etc., or even directly for 220V AC, and then transform to the front end.

Fourth, why can't PoE switch power supply exceed 30 watts?

At present, the single-port power supply of the PoE switch is 15.4W and 30W, and the power supply voltage is generally 48V. When the PoE switch is selected to supply power to the network device, the total power supply is a very important indicator. The power is small and the device cannot work.

So some people wondered why the single-port power can't be made more than 30W, such as 50W, 60W or 100W? Or increase the power supply voltage to 60V, 100V, etc. To answer this question, you need to understand the principle of PoE power supply.

PoE power is supplied through the network cable, which means that power needs to be transmitted in the network cable. We know that the network cable is generally used to transmit data signals. If the power signal is transmitted, there is a problem of resistance and endurance. If the voltage is set to 100V, the current transmitted through the network cable will be very high, exceeding the capacity of the network cable, causing many hidden dangers. Since the voltage can't be so high, the current can't be so high, then the power supply can't be so high.

Because PoE power supply, there are both data signals and power signals in the network cable. In order to prevent mutual influence and ensure good power transmission effect, the single-port power supply of the related equipment of PoE power supply specified by the industry cannot exceed 30W.