Question: What is the relationship between buses and protocols?

Fieldbus is an industrial data bus that has seen rapid development in recent years. It primarily addresses the issue of digital communication between intelligent instruments, controllers, actuators, and other field devices in industrial settings, as well as the transfer of information between these field control devices and higher-level control systems. Due to a series of outstanding advantages such as simplicity, reliability, and cost-effectiveness, fieldbuses have received significant attention from many standard-setting organizations and computer manufacturers. 　　Fieldbus is a network for interconnecting intelligent devices in fields such as process automation, manufacturing automation, and building automation, which was developed internationally in the late 1980s and early 1990s. It serves as the foundation for the digital communication network in factories, establishing connections between the production sites and control devices, as well as between them and higher levels of control and management. It is not only a grassroots network but also an open, new type of fully distributed control system. This integrated technology, which relies on advanced techniques such as intelligent sensing, control, computing, and digital communication, has attracted attention worldwide. It has become a focal point in the development of automation technologies and will lead to significant changes in the structure and design of automation systems and devices. Many powerful and influential companies around the world have successively developed fieldbus technologies and products to varying degrees. Fieldbus devices operate at the lower level of process equipment; as the fundamental communication network at the equipment level in factories, they are required to have simple protocols, strong fault tolerance, good security, and low costs. They also need to exhibit a certain degree of timing reliability and high real-time performance, as well as stable network load, with most data transfers being in the form of short frames and frequent information exchanges. Due to the aforementioned characteristics, fieldbus systems possess the features of higher-layer high-speed data communication networks, from their network structure to their communication technologies. 　　Fieldbus systems are generally referred to as the fifth generation of control systems, also known as FCS – Fieldbus Control Systems. Generally, pneumatic signal control systems PCS used before the 1950s are referred to as the first generation, electric analog signal control systems such as 4–20mA as the second generation, centralized digital computer control systems as the third generation, and distributed control systems DCS that have emerged since the mid-1970s as the fourth generation. As a next-generation control system, the Field Bus Control System FCS, on the one hand, overcomes the limitation of DCS systems that rely on dedicated communication networks by adopting open and standardized solutions, thereby eliminating the drawbacks associated with closed systems ； On the other hand, the distributed control system architecture that combines centralization and decentralization in DCS has been transformed into a new fully distributed structure, with control functions completely delegated to the field. It can be said that openness, decentralization, and digital communication are the most prominent features of fieldbus systems. Development History: In 1984, the American company Inter introduced a computer-based distributed control system called BITBUS. An overview of the development of fieldbus technology shows that this system separated the low-speed, process-oriented input/output channels from the high-speed computer buses (MULTIBUS), thus establishing the initial concept of fieldbuses. In the mid-1980s, the American company Rosemount developed an addressable remote sensor (HART) communication protocol. A frequency signal is superimposed on a 4–20mA analog signal, and digital signal transmission is achieved using twisted pair. The HART protocol is already the precursor to fieldbuses. In 1985, major companies such as Honeywell and Bailey initiated the creation of World FIP, which developed the FIP protocol. In 1987, a dedicated committee was also established, led by several well-known companies such as Siemens, Rosemount, and Yokogawa, to develop the Inter-System Protocol (ISP), and the PROFIBUS protocol was created. Later, the Instrumentation and Control Society of America also established the fieldbus standard IEC/ISA SP50. Over time, the world gradually saw the emergence of two competing groups of fieldbus standards: one is the ISP group led by Siemens, Rosemount, and Yokogawa ； The other is the WorldFIP group, led by companies such as Honeywell and Bailey. In 1994, the two groups announced their merger to form the Fieldbus Foundation, abbreviated as FF. Regarding the technical development and standard-setting of fieldbus technologies, the funding committee reached the following consensus: to jointly develop standards in accordance with the IEC/ISA SP50 protocol ； Agree on a timeline for the development stages of fieldbus technology. Technical features: Openness of the system. An open system refers to one in which communication protocols are made public, allowing devices from different manufacturers to be interconnected and to exchange information with each other. The goal of those who develop fieldbus technologies is to create open systems that form a unified underlying network within factories. Comparison of costs between fieldbus technology and traditional bus technologies. The openness here refers to consistency and transparency regarding relevant standards, emphasizing consensus and compliance with those standards. An open system that can be connected to any other device or system that adheres to the same standards. A fieldbus network system with bus functionality must be open; open systems grant users the right to integrate the system. Users can combine products from different suppliers to create systems of any size according to their own needs and objectives. Interoperability and Interusefulness Here, interoperability refers to the ability to enable information transfer and communication between interconnected devices and systems, allowing for point-to-point as well as one-to-many digital communications. Interoperability, on the other hand, means that devices with similar performance from different manufacturers can be exchanged to achieve interoperability. Intelligence and functional autonomy of field devices: It distributes functions such as sensing and measurement, compensation calculations, engineering quantity processing, and control to the field devices themselves. The basic functions of automatic control can be carried out solely by these field devices, and it is also possible to diagnose the operating status of the devices at any time. High degree of decentralization in system architecture: Since field devices are capable of performing the basic functions of automatic control, field buses have become the basis for a new architecture of fully distributed control systems. It fundamentally changed the existing DCS architecture, which combines centralized and decentralized control systems, simplified the system structure, and improved reliability. Adaptability to the field environment: Operating at the front end of on-site equipment as the field bus underlying the factory network, it is designed specifically for use in field environments. It can utilize twisted pair, coaxial cable, optical fiber, radio frequency, infrared, power lines, etc., and boasts strong interference resistance. It enables power supply and communication via a two-wire system, while also meeting essential safety and explosion-proof requirements. Technical advantages: Reduction in the number of hardware components and associated costs. Since the intelligent devices located at the front end of the equipment in a fieldbus system can directly perform various functions such as sensing, control, alarm generation, and computation, it becomes possible to reduce the number of transmitters. There is no longer a need for separate controllers or computing units, nor are there any requirements for functional units like those used in DCS systems for signal conditioning, conversion, and isolation, along with their complex wiring. In addition, industrial PCs can be used as operation stations, thereby saving significant amounts of investment in hardware. With fewer control devices, the space required in the control room can also be reduced. Cost savings on installation: The wiring of fieldbus systems is very simple. Since multiple devices can typically be connected to a pair of twisted pairs or a single cable, the amount of cable, terminals, junction boxes, and tray systems required is **reduced**, and the workload associated with wiring design and connection verification is also **decreased**. When it is necessary to add on-site control equipment, there is no need to install new cables; they can be connected to the existing cables, which saves costs and reduces the workload associated with design and installation. According to the calculation data from relevant typical test projects, installation costs can be reduced by over 60%. Reduced maintenance costs: Since the field control devices have the capability for self-diagnosis and simple fault handling, and send relevant diagnostic and maintenance information to the control room via digital communication, users can access information on the operation of all devices as well as diagnostic and maintenance data, which enables early identification of fault causes and rapid resolution of issues. It reduces maintenance downtime, and at the same time, the simplified system structure with simpler wiring reduces the amount of maintenance work required. 　　Cost comparison between fieldbus technology and traditional bus technology: Users have significant control over system integration. They can freely choose devices provided by different manufacturers to integrate the system. It prevents the selection range of devices from being limited by choosing products from a particular brand, avoiding difficulties caused by incompatible protocols or interfaces in system integration, and ensures that the user has full control over the system integration process. It improves the accuracy and reliability of the system. Thanks to the intelligence and digitization of fieldbus devices, it significantly enhances the accuracy of measurement and control compared to analog signals, while reducing transmission errors. At the same time, due to the simplified structure of the system, with fewer devices and connections, the internal functions of the field instruments have been enhanced: this reduces the back-and-forth transmission of signals and improves the reliability of the system’s operation. Furthermore, thanks to its standardized equipment and modular functions, it also boasts advantages such as simple design and ease of restructuring. Network Topology The network topologies for fieldbuses fall into four main categories: ring topology, star topology, bus topology, and tree topology. Introduction to Typical Fieldbuses There are currently over 40 different fieldbuses available internationally, but none of them can cover all application areas. Based on the size of the data they transmit, they can be divided into three categories: sensor buses, which involve bit-level transmission ； Device bus, which belongs to byte transmission ； Fieldbus belongs to data stream transmission. Foundation Fieldbus Foundation Fieldbus, abbreviated as FF, is a technology that enjoys widespread support in the field of process automation and holds good prospects for further development. Its predecessors were the ISP protocol, developed by American company Fisher-Rousemount in collaboration with 80 other companies including Foxboro, Yokogawa, ABB, and Siemens, and the WordFIP protocol, developed by Honeywell in partnership with 150 companies from Europe and other regions. Under pressure from users, these two major groups merged in September 1994 to establish the Fieldbus Foundation, with the goal of developing a unified international fieldbus protocol. It is based on the ISO/OSI open system interconnection model, adopting its physical layer, data link layer, and application layer as the corresponding layers of the FF communication model, with an additional user layer added at the application layer. 　　The Foundation Fieldbus comes in two communication speeds: low-speed H1 and high-speed H2. H1 has a transmission rate of 3125 Kbps, a communication range of up to 1900 meters (which can be extended with repeaters), supports bus power supply, and is suitable for intrinsically safe explosive-proof environments. The transmission rates for H2 are 1 Mbps and 25 Mbps, with communication distances of 750 m and 500 m respectively. The physical transmission medium supports options other than twisted pair, optical fiber, and wireless transmission, and its protocol complies with the IEC1158-2 standard. The transmission signal of its physical medium uses Manchester encoding, with the central point of each bit of data being either a positive transition or a negative transition. A positive transition represents 0, while a negative transition represents 1, thereby providing sufficient positioning information in the serial data bit stream to maintain timing synchronization between the sender and receiver. The receiver can determine the ‘1’ or ‘0’ state of the data based on the polarity of the transition, as well as pinpoint its exact position based on the center of the data. 　　To meet user needs, companies such as Honeywell and Ronan have developed specialized chips capable of handling the physical layer and some of the data link layer protocols. Many instrument manufacturers have created products that comply with the FF protocol. The FF fieldbus has passed both alpha and beta tests, with a factory test system based on devices from 13 different manufacturers having been implemented. A 2-bus standard has also been established. 　　In October 1996, at the ISA96 exhibition held in Chicago, organized by the Fieldbus Foundation, more than 70 products from over 40 manufacturers that complied with the FF protocol were showcased to the world. The FF products displayed in various booths across different floors of the exhibition hall were interconnected using prominent orange-red cables to form a seven-section Fieldbus demonstration system, allowing for real-time interoperability between the devices at each booth and thus demonstrating the achievements and technical capabilities of the Foundation’s Fieldbus technology. LonWorks is another powerful fieldbus technology. It was developed by the American company Ecelon, and it was promoted jointly by Ecelon along with companies such as Motorola and Hitachi. It was officially introduced in 1990. It utilizes all seven layers of communication protocols from the ISO/OSI model, adopts an object-oriented design approach, and simplifies network communication through network variables to parameter settings. Its communication speed ranges from 300bps to 15Mbps, with a direct communication distance of up to 2700 meters (at 78kbps over twisted pair). It supports various communication media such as twisted pair, coaxial cable, fiber optic, radio frequency, infrared, and power lines, and corresponding intrinsically safe explosion-proof products have been developed; it is thus regarded as a universal control network. 　　The LonTalk protocol used in LonWorks technology is implemented within chips known as Neurons. The integrated chip contains 3 8-bit CPUs: one is used to carry out the functions of layers 1–2 in the open interconnection model; it is called the media access control processor and is responsible for controlling and processing medium access. The second CPU is used to handle the functions of layers 3–6; it is known as the network processor, and it performs tasks such as addressing, processing of network data, background diagnostics, function path selection, software timing, and network management. It is also responsible for controlling network communications and sending/receiving data packets. The third CPU is an application processor that executes operating system services and user code. The chip also has information storage buffers to facilitate data transfer between CPUs, as well as serving as network buffers and application buffers. For example, the neuron integrated chip MC143120E2 produced by Motorola includes 2K RAM and 2K EEPROM. 　　The continuous spread of LonWorks technology has contributed to the low cost of neuron chips (with a price of around $5 to $9 per chip), and the low cost of these chips in turn has facilitated the further adoption of LonWorks technology, creating a positive feedback loop. According to information from Ecelon Corporation, by July 1996, 5 million neuron chips had been produced. 　　LonWorks Company’s technical strategy is to encourage OEM developers to use LonWorks technology and neuron chips to create their own application products. It is said that more than 2,600 companies are currently involved with LonWorks technology to varying degrees: over 1,000 of these companies have already launched LonWorks-based products, and they have also formed the LonWorks Interoperability Association to develop and promote LonWorks technology and products. It is widely used in industries such as building automation, home automation, security systems, office equipment, transportation equipment, and industrial process control. To support the interconnection and interoperability between LonWorks and other protocols and networks, the company is developing various gateways to connect LonWorks with Ethernet, FF, Modbus, DeviceNet, Profibus, Serplex, and others into integrated systems. 　　Furthermore, the LonWorks neuron chip also has unique advantages in the development of intelligent communication interfaces and intelligent sensors. The LonWorks technology has been designated by the American Society of Heating, Refrigerating and Air-Conditioning Engineers ASRE as a standard for the building automation protocol BACnet. According to recent news, the Consumer Electronics Manufacturers Association of the United States has passed a resolution to establish the EIA-709 standard based on LonWorks technology. 　　In this way, LonWorks has established a complete set of development, manufacturing, promotion, and application architectures that cover everything from protocol development and chip design to chip manufacturing, the development and production of control modules, OEM control products, end-control products, distribution, and system integration. This has attracted tens of thousands of enterprises to participate in this effort, which greatly facilitates the promotion and application of this technology. Profibus 　　Profibus is a fieldbus that corresponds to the German standard DIN 19245 and the European standard prEN 50170. The ISO/OSI model is also its reference model. The Profibus series is composed of Profibus-Dp, Profibus-FMS, and Profibus-PA. The DP type is used to distribute high-speed transmission between peripherals, and is suitable for applications in the field of process automation. FMS stands for Field Information Specification, and it is used in areas such as textiles, building automation, programmable controllers, and low-voltage switches within general automation applications. The PA type, on the other hand, is a bus type used for process automation, and it complies with the IEC1158-2 standard. This technology was developed jointly by Siemens and a dozen other German companies and research institutions. It utilizes the Physical Layer and Data Link Layer of the OSI model; these two layers constitute a subset of the first part of the standard. The DP type omits layers 3 to 7 and adds a direct data connection that serves as a user interface. The FMS type only omits layers 3 to 6 and incorporates the Application Layer as the second part of the standard. The standards for the PA type are still in the process of being established; its transmission technology complies with the IEC1158-2 (1) standard, enabling bus-powered operation as well as intrinsically safe explosion protection. 　　Porfibus supports several transmission modes, including master-slave systems, pure master station systems, and mixed multi-master multi-slave systems. The master station has control over the bus and can send messages proactively. In a multi-master system, information is transmitted between masters using a token; the station that obtains the token gains control of the bus for a predetermined period of time. A maximum time limit is also set for how long the token can circulate among the various masters. According to the Profibus communication specifications, the token is transmitted in the upward direction among the master stations in order of their address numbers. When it gains control, the master station can send or request information from the slave stations in a master-slave manner, thereby achieving point-to-point communication. The master station can broadcast to all stations (without requiring a response) or selectively broadcast to a group of stations. 　　The transmission rate of Profibus is 96–12 kbps; the maximum transmission distance is 1000 meters at 12 kbps and 400 meters at 15 Mbps. It can be extended to 10 kilometers using repeaters. Its transmission medium can be twisted pair or optical cable, and up to 127 stations can be connected. CAN 　　CAN is the abbreviation for Control Area Network, a control network that was first developed by the German company BOSCH. It is used for data communication between various measuring and actuating components within vehicles. Its bus specification has now been established as an international standard by the ISO International Organization for Standardization, and it enjoys support from companies such as Motorola, Intel, Philips, Siemens, and NEC; it is widely used in the field of discrete control. 　　The CAN protocol is also based on the Open Systems Interconnection model established by the International Organization for Standardization; however, its model structure consists of only 3 layers, taking only the physical layer and data link layer from the lower layers of OSI, as well as the application layer from the upper layers. Its signal transmission medium is twisted pair; the maximum communication rate is 1 Mbps over a distance of 40 meters, while the maximum direct transmission distance is 10 km per kbps. It can support up to 110 connected devices. 　　CAN uses a short-frame structure for signal transmission, with each frame containing 8 valid bytes; as a result, the transmission time is short and the likelihood of interference is low. When a node experiences severe errors, it has an automatic shutdown function that disconnects that node from the bus, ensuring that the other nodes on the bus and their communications are not affected, thus providing strong resistance to interference. 　　CAN supports multi-master operation, whereby any node on the network can actively send messages to other nodes at any time; it allows for data reception/sending in point-to-point, one-to-many, and global broadcast modes. It employs bus arbitration technology; when several nodes transmit data over the network at the same time, the node with a higher priority can continue transmitting its data, while nodes with lower priorities stop sending voluntarily, thereby avoiding bus conflicts. 　　Several companies have developed and produced communication chips that comply with the CAN protocol, such as Intel’s 82527, Motorola’s MC68HC05X4, and Philips’ 82C250. There are also CAN bus interface cards that can be plugged into PCs, offering advantages such as simple interfaces, easy programming, and low costs for development systems. HART 　　HART is the abbreviation for Highway Addressable Remote Transduer. It was first developed by Rosemout Company and supported by over 80 renowned instrumentation companies; the HART Communication Foundation was established in 1993. This open communication protocol, known as the Addressable Remote Sensing High-Speed Channel, is characterized by enabling digital communication over existing analog signal transmission lines. It represents a transitional solution for industrial process control during the shift from analog systems to digital systems; as such, it possesses strong market competitiveness in the current transition period and has seen good development. 　　The HART communication model consists of 3 layers: the physical layer, the data link layer, and the application layer. The physical layer uses FSK (Frequency Shift Keying) technology to superimpose a frequency signal on the 4–20mA analog signal; the frequency signal adheres to the Bell202 international standard. The data transmission rate is 1200bps, with the signal frequency for logic 0 being 2200Hz and the signal frequency for logic 1 being 1200Hz. 　　The data link layer is used to establish the HART information format in accordance with the rules of the HART communication protocol. Its information structure includes a start code, the addresses of the display terminal and the field device, the number of bytes, the status of the field device and communication status, data, parity check, etc. Its data byte structure consists of 1 start bit, 8 data bits, 1 parity bit, and 1 stop bit. The role of the application layer is to implement HART commands, that is, to convert the communication status into corresponding information. It specifies a series of commands; it operates in accordance with those commands. It has 3 categories of commands. The first category is called general commands, which are the commands that all devices can understand and execute. The second category is known as general behavior commands; the functions they provide can be implemented in many field devices (though not all of them), and this category includes the function sets of the most commonly used field devices. The third category is called special device commands, which are used to enable special functions in certain devices. Such commands can either be made available to the industry as a whole or remain exclusive to the company that developed them. These 3 types of commands are usually found to exist simultaneously in a field device. HART supports point-to-point master-slave response and multi-point broadcast modes. When operating in the response mode, the data update rate is 2–3 times per second; when operating in the broadcast mode, the data update rate is 3–4 times per second. It can also support two communication master devices. Up to 15 devices can be connected to the bus; each field device can have 256 variables, and each message can contain up to 4 variables. The maximum transmission distance is 3000m, and HART uses a unified device description language called DDL. Field device manufacturers use this standard language to describe the characteristics of devices. The HART Foundation is responsible for registering and managing these device descriptions, compiling them into a device description dictionary. Master devices utilize DDL technology to understand the characteristic parameters of these devices, thereby avoiding the need to develop dedicated interfaces for them. However, due to this analog-digital mixed-signal format, it is difficult to develop a communication interface chip that can meet the requirements of various companies. HART can utilize bus power, meeting intrinsically safe explosion-proof requirements. RS-485 　　Although RS-485 cannot be considered a field bus, as the pioneer of field buses, many devices still use this communication protocol. Using RS-485 communication offers advantages such as simple equipment and low cost, and it still retains its relevance. The OPTO-22 command set, based on RS-485, is also widely used in many systems. Technical Outlook and Development Trends The development of fieldbus technology should manifest in two aspects: one is the continued advancement and improvement in the field of low-speed fieldbuses ； The other is the development of high-speed fieldbus technology. 　　Currently, fieldbus products are mainly low-speed buses, used in fields with lower operating speeds where the performance requirements for the network are not very high. In terms of application scenarios, whether it is FF and Profibus or other fieldbuses, they can all effectively meet the requirements of process control with lower speed demands. Therefore, in control fields with lower speed requirements, it is very difficult for anyone to unify the entire global market. One of the key technologies for fieldbuses is interoperability, and achieving standardization of fieldbus technology is the desire of all users. How fieldbus technology will develop and be standardized in the future is a matter of great concern to all manufacturers and users. 　　High-speed fieldbuses are primarily used for interconnection within control networks, connecting devices with high levels of intelligence and fast processing speeds such as control computers and PLCs, as well as for establishing connections between low-speed fieldbus bridges. They are essential for fully realizing a fully decentralized control structure for the system. This field is still relatively weak at present. Therefore, the design and development of high-speed field buses will be a highly competitive field, and it will also represent an important opportunity for the standardization of field bus technology. Choosing which network technology to use as the overall framework for high-speed field buses will be its primary concern. 　　The development of fieldbus technology has become a topic of great interest in the field of industrial automation. International research and development in fieldbuses have enabled measurement and control systems to break free from the constraints of traditional closed systems and embark on a path of open development. This presents an excellent opportunity as well as a severe challenge for the development of fieldbus control systems in our country. The networking of automation systems is a major trend in development, and fieldbus technology has been profoundly influenced by computer network technology. With network technology advancing at an ever-increasing pace, some new network technologies with significant impact will undoubtedly be further integrated into fieldbus technology. Among these promising fieldbus technologies are ； Software and hardware technologies for the development of smart meters and network devices ； Configuration of the network infrastructure, including network topology, network devices, and interconnection between network segments ； Network management technologies, including network management software, as well as network data manipulation and transmission ； Human-computer interface, software technology ； Fieldbus system integration technology. 　　Generally speaking, automation systems and equipment will move toward fieldbus architectures, and this trend is certain. Since it is a bus, it should evolve in a direction toward openness and standardization, becoming a standard specification that everyone follows. However, this technology is applied in a very wide range of fields, covering almost all continuous and discrete industrial areas such as process automation, manufacturing automation, building automation, home automation, and so on. In the vast world, with its many different fields and varying requirements, a single fieldbus system may accommodate more than one standard. Each of these major technologies has its own characteristics and has established its own advantages in various application areas. Driven by commercial interests, they are all striving for growth in a highly competitive market. It is reasonable to assume that over the next 10 years, several major bus standards may coexist; indeed, within a single fieldbus system, devices using different bus standards could be interconnected through routing gateways to enable information sharing. In the field of continuous process automation, over the next 10 years, the FF Foundation Fieldbus will become the dominant trend, LonWorks will be a strong competitor, and HART, as a transitional technology, will also hold a certain market share. These 3 technologies stem from the industrial needs in this field; the various functions of their user interfaces are designed for professional continuous process engineering, and they take into full account the operating conditions in continuous industrial environments, such as supporting bus-powered operation and meeting intrinsic safety and explosion-proof requirements. 　　Furthermore, the FF Foundation brings together almost all of the world’s major manufacturers of automated instrumentation ； LonWorks has established a comprehensive system of division of labor and cooperation. These factors are crucial for becoming the mainstream technology in this field. Since HART is built on the currently widely used analog systems, it can take full account of the benefits of existing equipment and prior investments, and its technology also fully meets the requirements of continuous process environments. It currently holds a certain market share, and its technology is continuously being improved and updated, such as by increasing the transmission speed. At present, the market share of HART instruments abroad continues to grow and is on an upward trend; however, it is after all a transitional product, and its lifespan will not be very long. In China, since many projects are new, less consideration is given to compatibility while more emphasis is placed on advancement; it is believed that HART will not hold a large market share in China. There are significant differences between the domestic market and the foreign market. On the one hand, products that are dominant in foreign markets will continue to penetrate the domestic market; on the other hand, since domestic manufacturers are relatively small in scale and have weaker R&D capabilities, they rely more on the support of technology suppliers, and are thus prone to being influenced by the support and marketing efforts provided by fieldbus technology suppliers (such as chip manufacturers) in the domestic market. Currently, only the LonWorks technology has significant market activity in China; therefore, most domestic manufacturers will first adopt this technology. Although FF is touted as the future standard in the instrumentation industry, its market share will be significantly affected due to the lack of a clear market strategy and active marketing efforts in the domestic market. Furthermore, facts show that all members of the Fieldbus Foundation (FF), while developing products that comply with FF standards, also introduce applications using LonWorks technology, which demonstrates the strong viability of LonWorks technology. In the field of discrete manufacturing, due to the characteristics of industry applications and historical reasons, there are some differences in the mainstream technologies used. Profibus and CAN are highly competitive in this field. They have already developed their own advantages in this field. In areas such as building automation, home automation, and smart communication products, LonWorks has unique advantages. Due to the characteristics of LonWorks technology, there will be significant development in its application across various control systems. 　　The rise of fieldbus technology has opened up new possibilities for the underlying networks in factories. It will accelerate the rapid development of enterprise networks and bring new benefits to enterprises; as a result, it will be widely used and drive the growth of industries related to automation.