The principle of access control system
Currently on the market of products, there is a control of a door, a control 2, a control 4, etc., that is, a controller, control 4 doors, each door with a card reader, an electric lock, 1 Room open button. 2. Access to the work of the process of the system is the process: the authorized proximity card close to the reader, the information sent to the controller, the controller CPU will read the data from the reader and the memory of the data after processing , There are three possible outcomes. First, the incoming data is generated by an authorized card, the time of the card is allowed to open the door of the time, these two conditions at the same time to meet the instructions to the control lock, electronic lock to open, while generating sound or light tips. Second, when the incoming data is generated by the unauthorized card, or non-open door period, do not send instructions to the electronic control, the card is invalid, the door can not open. If someone's proximity card is lost, the acquirer can not enter the non-working hours illegally. Third, when the security personnel to read the card, the system program for a record, but the electric control lock is not action, in the tour management terminal display, easy to attend the attendant at any time to grasp the situation of patrol officers. If you need to come out from the room, press the door open button switch, the controller received the information after the electronic lock to issue instructions, electronic lock to open. The door closers automatically assist the doors off.
Network access control system is controlled by the controller, card reader, electronic control. Open the door button and other components, is the system integration of the underlying control layer and executive layer. (1) controller: is used to collect the information from the reader to process, issue instructions to control the opening of the electronic control lock; storage card data data: complete the bus networking functions. (2) card reader: read the information on the card and upload to the controller, it can match, can also be optional, as long as meet the interface requirements can be; installation location in the door close. (3) sensor card: is used to store personal information IC or ID card, which contains an integrated circuit and induction coil. When the proximity card is close to the card reader, the information stored in it is passed to the card reader in the way of induction to achieve the purpose of opening the door. (4) electric lock: access control is the actuator, control the door "open", "off" state. The installation location is on the door frame or door leaf in the room. (5) open the door button: the room is open to the staff of the door switch, the installation location is close to the door in the room.
The function setting of the access control system is done on the PC workstation in the form of a desktop. These functions include the door opening time setting, the induction card authorization, the corresponding setting of the card number and the controlled door, the attendance statistics report, the patrol card number setting. By modifying the program, to achieve access control systems and other systems linkage. The network administrator has the right to open any door on the workstation. 3. Access control system integration A network access control system is composed of many gantry, the gates between the RS485 bus and access control network controller connected to form a door access network system. The network through the Ethernet bus and computer LAN connected to form a three-tier system integration, three-tier network structure, you can from top to bottom, to achieve management control. The lower layer network can be controlled by the upper layer management, can also rely on the upper and independent work, when the upper layer failure or disconnect the link, it will not affect the layer and the lower normal work. This will not only improve the degree of intelligent access control network, but also improve the reliability of each controller.
Stand-alone access control is non-network type, each door locks are independent, the information read is usually card and induction type, the advantage is low cost. This article does not make a specific analysis of the independent access control, focusing on the analysis of network-based access control system.
Access control is a CPU processor as the core of the controller, information collection and electronic control lock and other components of the control network system, through the system information read. Processing, to achieve a variety of door lock switch automatic control. According to the information read the way can be divided into: card, induction, image recognition, eye iris recognition and so on. Their scientific and technological content and system cost order in turn increased.
