As we know, there are three power supply modes in the surveillance system.

1. Independent power supply mode

2. Centralized power supply mode

3. PoE power supply supply mode. In this mode, it includes 4 types of PoE.

Then, you may doubt what kind of power supply is the ideal choice. And what should we pay attention to when we select the power supply for our cameras? Let's start with the basic knowledge of the three modes.

INDEPENDENT POWER SUPPLY MODE

In this mode, the cameras are powered by independent power supplies. The schematic diagram is as follow:

ADVANTAGES

1. Convenient to repair and replace the power supply

You can quickly troubleshoot the fault cameras. If the fault caused by the power supply, you just need to repair or replace the power supply only.

2. Protect the surveillance system from breakdown

A problem with the power supply system in centralized mode without UPS power will cause the entire surveillance system to fail and go down. In the independent power supply mode, a single or several cameras cannot work due to the failure of the power supply can not lead to the breakdown of the system.

DISADVANTAGES

1. Excessive cost

The sum of the costs of multiple independent power supplies is generally higher than a centralized power supply with the same power output. This cost does not take into account the cost of cables.

2. More likely to be damaged by external forces

Because the independent power supply is often close to the camera, if it is outdoor, it is more vulnerable to sun, rain, lightning, and other external factors. Therefore, choose an independent power supply for outdoor use, and pay particular attention to the protective performance of this independent power supply.

CENTRALIZED POWER SUPPLY MODE

Connect a 12V centralized power supply at the 220V power supply, and then connect the 2*1.0 red and black power cord to the camera. Please note that the distance of the 12V power supply should not exceed 100 meters. Connect a single power cord connector and then it to the surveillance camera power connector. A centralized power supply is one that uses a 12V switched power supply in the monitoring room or at some intermediate point to provide centralized power to the front equipment. The big difference compared to the independent power supply mode is that multiple cameras are powered by one power supply. The schematic diagram is as follow:

Data centers are managed for both infrastructure and IT infrastructure, such as power distribution, network equipment, security, etc.

The purpose of centralized monitoring is to monitor the operation of infrastructure and IT infrastructure through the application of management and technology to achieve real-time detection and notification of faults and anomalies. Also, monitoring data collection and collation can provide the basis for the analysis of capacity management, event management, problem management, compliance management, and ultimately achieve the goal of high data center availability.

ADVANTAGES

1. Lower cost

Although the centralized power supply mode often uses more cables than the independent power supply mode, it is often the most cost-effective power supply system due to the high price/performance ratio.

2. Easy centralized maintenance

Easy deployment, easy construction and easy management.

3. Low power consumption

The total power consumption of centralized power supply mode is lower than independent power supply mode, as proven by actual engineering cases.

DISADVANTAGES

1. Complex earlier-stage configuration

The centralized power supply does not add up to the power of all the surveillance cameras since they require a large starting power supply at the moment of start-up, and power delivery over long distances can cause losses. Therefore, it requires the engineer to have a thorough understanding of the entire monitoring system to make a rational decision in the centralized power supply mode.

In fact, due to the high starting current of the camera at the moment of start-up and the loss of long-distance transmission on the project, it is not simply to add up the rated power of all cameras for selecting the power supply. The correct way is to add up the rated power of the cameras in the entire surveillance system multiplied by 1.3 times, which is the actual power required by the camera, then add about 30% of the loss, and finally, add 30% of the remaining capacity for future expansion.

2. There is a possibility that the surveillance system may be down.

A problem with the power supply system in centralized mode without UPS power will cause the entire surveillance system to fail and go down.

POE (POWER OVER ETHERNET)

There are four main types of POE power supply.

1. Both Ethernet switches and terminals support PoE.

This method of connecting PoE switches directly to PoE-powered wireless APs and network cameras via a network cable is the simplest, but also requires attention to the following two points.

A. Determine whether PoE switch and AP or IP camera are standard PoE equipment.

B. The quality of the cable is very important. A poor quality cable will cause the AP or IP camera to fail or restart constantly.

The schematic diagram is as follow:

2. Ethernet switches support POE, terminals do not support POE

In this solution, PoE switch is connected to PoE splitter, which separates the PoE into data signal and power. The power output has 5V/9/12V, etc., can match various DC input non-PoE powered terminals. The data signal output cable is a normal network cable that is directly connected to a non-PoE powered terminal's network port.

The schematic diagram is as follow:

3. The switches do not support POE, the terminals support POE.

In this solution, the PoE injector is connected between Ethernet switch and terminals. It facilitates the expansion of the legacy cabling network and has no impact on the legacy network.

The schematic diagram is as follow:

4. Both Ethernet switches and terminals do not support PoE

In this solution, it needs the PoE injector and PoE splitter. The schematic diagram is as follow:

HOW TO CHOOSE BETWEEN INDEPENDENT AND CENTRALIZED POWER SUPPLY?

Generally speaking, it is suitable to use the independent power supply in the surveillance system below 4 channels. And it is recommended to use the centralized power supply in the 4 to 16 channels surveillance system if the distance is similar. On the condition of finished early-stage configuration, you can use multiple centralized power supplies for the over-16-channel surveillance system.

Eg:

If a business building has 100 fixed-gun network cameras, the rated power of each camera is 4W, how should we configure the camera power?

- According to the above calculation method, we calculate that the rated power of the camera is 4W*100 units = 400W.

- The actual power used by the camera is 400W*1.3 = 520W.

- Taking into account the loss, the power required by the camera is 520W*1.3 = 676W

- Adding remaining capacity for future expansion, the final configuration of the camera power is 676W*1.3 = 878W.

SUMMARY

The total power supply power of cameras = the rated power of the camera * 1.3 * 1.3 * 1.3

(Note: If the distance is particularly long, you need to increase the power supply power, and increase the supply voltage)

WHAT SHOULDN’T DO IN THE CONFIGURATION OF POWER SUPPLY?

The answer is to use only one power supply for the entire surveillance system.

The reasons are as follows.

1) It is often necessary to turn the power on and off during system maintenance. All cameras start at the same time when the power is turned on at the same time, the starting current is particularly high, the impact on the power supply is very strong, and severe will burn the power supply.

2) All cameras share one power supply and when the power fails, the entire closed-circuit surveillance system goes down.

In particular, images of some important entrances and exits cannot be monitored and can cause unnecessary trouble.

So what's the right thing to do? For example, in the above example, a business building has 100 fixed cameras, requiring a total of about 800W of power supply, the correct configuration should be to select 4, each with 200W of power. This way, when one power supply fails, the camera at the important entrance and exit can be connected to another good power supply, without affecting the work of the whole system.