As a security sub-system in the weak power system, we often encountered, almost all building projects have this system, because the access control system will be equipped with personnel management. There is a very important device in the access control system, namely the access control power supply. What is its function? How to choose it? Let's talk about it together today.
Although the access controller is the core part of the access control system, the power supply is also a non-negligible part to ensure the stability of the whole system.
Choose linear power supply or switching power supply?
Advantages of linear power supply:Stable performance, no interference such as high frequency ripple.
Disadvantages of linear power supply:Heat generation and low energy utilization. Choose a power supply that does not have excessive power.
Advantages of switching power supply:Convenient to centralize power supply using high power supply. Show better cost performance when raw material prices rise. Small size and light weight. Many brands and models available.
Disadvantages of switching power supply: If the power supply quality is not good, the high frequency ripple control is not good, for some poor anti-interference ability of the access controller, it is easy to cause the death of the access controller, resulting in the inability to open the door.
My opinion and suggestion:I think it can be chosen. If you choose switching power supply, it is recommended to choose brand switching power supply, which requires the controller to be anti-interference.
How much power supply is suitable to choose?
The power of the vast majority of access control systems using 12V power supplies can be evaluated by the power supply's rated current parameter. Considering the shock resistance and long-term stable operation, the following recommendations are made:
If a linear power supply is chosen, it is recommended to choose a nominal 5-7A linear power supply if the controller has 4 electric plug locks calculated. If the controller has 1 plug-lock calculation, it is recommended to select a nominal 3A linear power supply as described above. If the controller has 4 plug-lock calculations, it is recommended to select the nominal 4-5A switching power supply. If the controller has 1 unplugged calculation, it is recommended to select the nominal 3A switching power supply described above. If the controller has 8 electric plug locks or 6 magnetic locks, it is recommended to choose 10 A above switching power supply.
Caution:
Power supply selection, the higher the power and rated current, the better, the side effects will not be too great. If it is very low, it will not work. There are many irresponsible power supply manufacturers in the market that falsely label the current and power ratings of their products. Therefore, it is recommended that you purchase a branded power supply.
Power supply is the foundation for ensuring the stable operation of the whole access control system. The choice of power supply can directly determine whether the engineer can get as much profit as possible when implementing the project. At the same time, the choice of power supply can also reflect the ability of engineers to control the quality of the project.
When investigating the whole access control macro market, we found that more than 90% of system failures are caused by improper power supply selection, and some failures may affect the smooth promotion of the project. Generally speaking, power supply failure is mainly manifested in the following aspects:
① Insufficient power supply after a period of use;
② After a thunderstorm, large-scale power failure;
③ Hot and cold weather, power supply failure;
④ Batteries are often bad, unable to power off to maintain normal operation of the system;
⑤ Short circuit causes power supply to burn out;
⑥ Insufficient power supply during the peak period of power consumption.
Application and selection of power supply for access control alarm system
1.Measure the actual output power of the power supply
Access control alarm system involves a variety of power supply equipment. In order to ensure the normal and stable operation of each device, the power supply needs to have enough power to supply each device. Purchase of power supplies, should pay special attention to the nominal value of the power supply, *** field test of the actual parameters, because some low-priced access control power supply on the market in the actual application of the power supply is often less than the nominal value, which seriously affects the normal and stable operation of the access control alarm system. It is recommended that the purchase of power supply to choose the technical parameters up to standard, reliable quality, good reputation, applicable to the access control alarm system power supply manufacturers. At present, some access control manufacturers sell power supplies together with controllers. Generally speaking, these manufacturers consider the actual application of the project and better ensure the overall quality of the system.
A simple way to test the output power of the power supply: add a load (such as a cement resistor) to the power supply that corresponds to the output power of the power supply, run it for more than 48 hours, measure the actual output voltage and current of the power supply with a multimeter and compare it with the nominal value, and test whether the output voltage is stable after loading? Is the heat normal? If the conditions allow, **** on-site installation and test run.
2. effective lightning protection
Determine whether the product has lightning protection:
① Visual inspection of the power supply on whether the design of the protection circuit. (This method applies to circuit hardware researchers).
② Find out whether the manufacturer has accumulated lightning protection technology that
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