Abstract: Applying embedded systems to the field of instrumentation, combining traditional instruments, the Internet, and microprocessors, has become a trend in the development of the instrumentation industry. This paper first introduces the embedded controller through a remote monitoring system based on embedded intelligent instruments. Then, combining the embedded controller, the author elaborates on the application of UML-RT and platform concepts in the design of embedded controller systems, and provides detailed steps and specific content for embedded controller design. Keywords: Embedded controller; Intelligent instrument; Microprocessor; UML-RT 1 Introduction While instrumentation is developing rapidly, computer and network technologies are also developing rapidly. PCs have transitioned from high-speed growth to a period of stable development. The emergence and widespread application of embedded systems have ushered in the post-PC era for computers and networks. Remote monitoring systems based on embedded intelligent instruments are one of the important development directions of industrial control networks. Embedded controllers are key devices for realizing remote monitoring of intelligent instruments and serve as a bridge between industrial control instruments and the Internet. 2 Controller Overview The structure of the embedded intelligent instrument and its connection scheme with the Internet are shown in Figure 1. [align=center]Figure 1 Remote Monitoring System Based on Embedded Intelligent Instruments[/align] An embedded controller is a control system used to perform independent functions and has the ability to process data in complex ways. It is built into industrial instruments and consists of three parts: a high-speed processor, an embedded web server, and an industrial instrument interface. The embedded controller uses a high-speed processor as its core, and the high-speed processor and other chips work together to control electronic devices or devices, capable of performing various automated processing tasks such as monitoring and control. The embedded controller is a good basic access device, connecting to instruments through the industrial instrument interface. Based on TCP/IP data transmission, the embedded controller integrates web functionality into the entire device. Customers only need a browser to easily communicate with the controller, view and set process parameters of the field intelligent instruments, and control the opening and closing of objects. The core of the remote monitoring system based on embedded instruments is the embedded controller. The embedded controller is a typical embedded system, and its system design follows the relevant theories of embedded system design. System design needs to consider the software and hardware structure as a unified and coordinated whole. Embedded systems tend to use high-platform architectures and object-oriented UML-RT for system analysis and design. Therefore, when designing the embedded controller, we adopted UML-RT and a platform to give the embedded controller a flexible architecture, enabling convenient and rapid changes or expansions of functions to meet system requirements. 3. Requirements Analysis of the Embedded Controller We used UML use case diagrams to analyze the requirements of the embedded controller. Use case diagrams describe the functions of the system hardware and software from the user's perspective. Based on our previous description of the embedded controller's functions, we derived the system's use case diagram, as shown in Figure 2. This includes seven different use cases and two different roles. [align=center]Figure 2 Use Case Diagram of the Embedded Controller[/align] The user role can view data, set data, and turn the controlled object (smart meter) on and off. The controlled object can receive and send data, and correspondingly perform on/off operation commands. The data processing center is responsible for data encapsulation, transmission, calculation, and other data processing tasks. 4. Platform Partitioning and Design After completing the system requirements analysis, we began to partition the system structure of this platform. The so-called system structure of this platform refers to the definition of the interfaces between each level of the platform system and the functional allocation between the upper and lower layers, and each layer has its own system structure. The system is primarily structured hierarchically based on function and logical order. When dividing the system structure, the following issues need to be considered: 1. Essentially, it represents the platform's attributes as seen by users during development, including conceptual structure, interfaces, and functional characteristics. Viewing it conceptually and functionally as a multi-level hierarchical structure facilitates a correct understanding of the embedded controller and development platform itself. It's necessary to determine which aspects should be transparent and which should not. Transparency simplifies the design of that level by eliminating the need for intervention. 2. Generally, many functions can be placed in either the upper or lower layers, and they are logically equivalent. The choice of upper/lower layer allocation depends on usability, complexity, and existing hardware conditions. 3. Determining from which layer the system structure design and implementation should begin is also crucial. For example, a three-layer structure can be implemented from top to bottom, bottom to top, or from the middle. Considering the above points, the system structure of the embedded controller platform is shown in Figure 3. We divide the embedded controller system into three abstraction layers: the Architecture Platform (ARC platform), the Application Programming Interface Platform (API platform), and the Custom Application Platform (ASP). The ARC platform includes the microprocessor storage system, interface circuits, I/O channels, and internal connections between chips. The microprocessor system consists of a family of "microarchitectures," including the S3C2410 microprocessor, FLASH, SDRAM, and the CS8900A network control chip. The API platform includes the RTOS (Real-Time Operating System), embedded web server, and device drivers. The API platform is a software abstraction layer that encapsulates the implementation details of the ARC platform. The API platform provides interface services and groups these interfaces by category. For example, users need to know whether the RTOS provides a preemptive task scheduling interface, or whether the embedded web server provides HTTP and TCP/IP interfaces. The ASP platform provides a direct user interface and specialized application services, such as allowing users to view and set control parameters of smart meters through a browser. [align=center]Figure 3 Platform Division[/align] Each platform has corresponding Quality of Service (QoS) requirements. The ARC platform has requirements for power consumption, storage capacity, processing speed, and communication capabilities. Chips such as S3C2410 and CS8900A can well meet these requirements. API platforms also have requirements regarding the number of running tasks and task switching time; embedded web servers and embedded Linux can meet these requirements. ASP platforms require real-time parameter viewing and setting; Java Applets can do this well. Dividing the embedded controller system into platforms and proposing corresponding service quality parameters for each platform allows us to have a global perspective on the entire design from the initial design stage. Because each platform is relatively independent, it has good adaptability to new design requirements and modifications that may arise later. 5. Embedded Controller Design Based on UML-RT After dividing the embedded controller into platforms, we can use the UML-RT notation system to model the embedded controller system. We divide the modeling process into two stages. The first stage considers the system's external interfaces. The second stage considers the internal platform modeling of the system. In the first stage, the embedded controller modeling is shown in Figure 4. Based on the requirements analysis of the previous use case diagram, we find that the system needs to interact with the environment through two ports: one is communication with the controlled object, i.e., the intelligent instrument; the other is interaction with the user. To support user interaction and communication with controlled objects, we define two containers: u (User Interface) and t (Transfer Data). The container p (Process Data) is used to process data. Containers can contain related software and hardware structures. Data transfer can be performed via parallel and serial ports, and this transfer is tightly coupled to the processor; we use extended notation in UML-RT. Similarly, SW p1 represents the program executing on processor P1 that handles communication with controlled objects. We can further refine u (User Interface) and p (Process Data) in this way. [align=center] Figure 4: First-stage representation of the embedded controller[/align] Based on the first stage, we combine the previous platform division to perform platform modeling. The modeling of the system's ARC platform is shown in Figure 5. [align=center] Figure 5: UML-RT modeling under the ARC platform[/align] Figure 5 shows the basic components of the ARC platform and their topology. This diagram can be used for further object modeling. This model provides a framework and allows for easy addition, movement, substitution, and modification of elements within the framework. UML-RT ports can effectively represent the interfaces between model elements. The API platform sits between the ARC and ASP platforms, including the RTOS embedded web server, device drivers, etc. From a UML-RT perspective, the API platform is the communication channel between the ARC and ASP containers. Here, the ARC and ASP containers are directly connected through a connector. The ARC Proxy receives call information from the ASP container's port and then sends this information through the RTOS API to the appropriate device driver, allowing the device driver to communicate with the ARC platform. Asynchronous or synchronous communication can be performed in this way. The driver and RTOS are closely related. The modeling of the ASP platform can also be represented in a similar way. In summary, by combining UML-RT and Platform for embedded controller design, we see that they can effectively abstract embedded hardware and software and provide good documentation. The system architecture designed based on UML-RT and Platform has good adaptability to new design requirements and modifications that arise during the design process, allowing designers to identify and correct errors early. The author's innovation: The convergence of control networks and information networks is a trend in enterprise informatization, and industrial Ethernet is playing an important role in this convergence process. This paper discusses the necessity and inevitability of combining embedded systems with Internet technology. It then presents an implementation scheme for a remote monitoring system for embedded intelligent instruments and introduces the basic structure of embedded intelligent instruments, clarifying the role of the embedded controller in realizing remote monitoring. About the author: Tang Liwei (1969 - ), male, from Loudi, Hunan Province, graduated from Xiangtan University with a major in Automation, lecturer in the Department of Mechanical and Electrical Engineering at Loudi Vocational and Technical College, research direction: electrical automation and numerical control technology. Biography: TANG Liwei (1969-), Male, Born in Hunan Loudi, Lecturer, Bachelor Degree, Research Areas: Electrical Automation and Digital Control Technology. Detailed mailing address: Department of Mechanical and Electrical Engineering, Loudi Vocational and Technical College, Hunan Province Recipient: Tang Liwei References [1] Li Qian, Ding Xiangqian, Shi Shuo, Jiang Zhaoning. Design of intelligent terminal based on embedded system platform [J]. Microcomputer Information, 2007, 3-2: 25-26. [2] Li Youjun. Overview of embedded systems [J]. Modern Electronics Technology, 2003, 11. [3] Zhou Gongle, Wang Jindi, Tang Shihao, Hu Ni, Zhao Feng, Zhao Kaiguang. Research on key technologies in the construction of remote sensing model library based on Web [J]. Remote Sensing Information, 2004, (1): 38-40. [4] Wang Jiezhi, Chen Zhigang. Using WEB services to implement intelligent client applications [J], Computing Technology and Automation. 05, 1. [5] Intelligent Client Architecture and Design Guide (Chapter 4) [M]. Microsoft MSDN 2004-8-20