introduction With the development of computer technology, communication technology and network technology, intelligence has gradually penetrated into people's family life. Smart home network refers to the connection of various electrical equipment and electrical subsystems through a certain transmission medium (such as twisted pair, power line, etc.) within the home, using a unified communication protocol to achieve internal resource sharing, and external gateways Extranet interconnection for information exchange. The system can perform centralized or distributed, local or remote control and management of various electrical equipment in the home. Because of its simple operation, good stability, easy expansion, flexible control and easy maintenance, the home network system has been widely used in many aspects such as home, industry, trade and commercial buildings. 1 HBS communication protocol The Home Bus System (HBS) is a concept jointly proposed by Japanese companies: Hitachi, Mitsubishi, Panasonic, Toshiba, etc., formulated by the Japan Electronics Industry Federation / HBS Standards Committee of the Wireless Engineering Electronics Association. HBS uses twisted pair or coaxial cable as the communication medium. The control channel can have up to 64 nodes. Household appliances are interconnected via the HBS bus to form a complete home network. The protocol is mainly used for the control of electrical switch quantity and simple analog quantity. It uses a dedicated bus, which has the advantages of strong anti-interference and high safety. The HBS protocol simplifies the open system interconnection (OSI) seven-layer model proposed by the International Organization for Standardization (ISO), citing layers 1, 2, and 7 of them, consisting of a three-layer structure, divided into a physical layer and data link Layer and application layer. The physical layer describes the signal mode and transmission medium. The signal line uses ordinary twisted pair. The signal on the HBS bus adopts pulse width coding. Since the selected HBS communication chip requires the maximum transmission signal frequency to be around 10 kHz, a low level of 50 μs is used, and a high level of 50 μs indicates logic “0â€; a low level of 50 μs and a high level of 150 μs indicate logic “1â€, such as Figure 1. In this way, the anti-interference ability is strong. The receiving end judges the logic "0" and logic "1" by calculating the time between two falling edges. The data link layer of the protocol is mainly the design of the communication frame structure. Communication is carried out in the form of frames. All frames sent from the host module are of fixed length. The contents of the data frame include the start byte, address byte, data byte, and check byte. The check method uses a simple checksum method to check the frame. First add the start byte, address byte, and data byte, and then truncate the result to the required bit length. The response frame of the slave module includes address byte, data byte and end byte. The application layer defines all the transmitted information so that the information transmitted on the network has a unique interpretation in the entire system. 2 The overall structure design of the system Figure 2 shows the overall structure of the system. It can be seen that this is a distributed bus system, and information is shared among nodes. With this structure, if you do not want to use a device or a device is damaged, you can directly remove it without affecting the system operation. There is only one master module in the whole system, and each slave module is connected to the bus. Each communication is initiated by the master module and ends with the response of the slave module. The host module sends the command code and encodes the command code to the bus. The slave module decodes the command code, so that the processor performs the corresponding operation and returns a response. The drive module is a specific drive unit that drives specific objects, such as light switches and brightness adjustments, power switches, warning lights, and alarm bells. Our company specializes in the production and sales of all kinds of terminals, copper terminals, nose wire ears, cold pressed terminals, copper joints, but also according to customer requirements for customization and production, our raw materials are produced and sold by ourselves, we have their own raw materials processing plant, high purity T2 copper, quality and quantity, come to me to order it! Cable Terminals Taixing Longyi Terminals Co.,Ltd. , https://www.lycopperlugs.com
