Abstract: Intelligent field monitoring devices are the foundation and key to building control networks. Developing Ethernet-based intelligent field devices using high-end embedded technology is an important development trend. This paper proposes a monitoring system based on embedded industrial Ethernet technology, detailing the hardware and software design process of the embedded industrial Ethernet monitoring device, including the implementation of a 32-bit microprocessor system, the implementation of Ethernet interface unit modules, the analysis and porting of the uCLinux embedded operating system, the analysis and implementation of drivers under uCLinux, Socket analysis, HTTP protocol analysis, and the implementation of an embedded web server. Keywords: Monitoring system; Industrial Ethernet; Embedded; Microprocessor 1 Introduction Since the 1970s, the TI industry, represented by network communication technology and microelectronics technology, has flourished. The rapid development of information technology has led to profound changes in the structure of automation systems, and enterprise information systems based on multi-level, network-integrated automation systems have gradually taken shape. The application of embedded systems to Ethernet is gradually entering the field of industrial control. This paper proposes a high-performance, low-cost overall design scheme for an embedded industrial Ethernet monitoring system. 2 Overall Design of the Embedded Industrial Ethernet Monitoring System The conception and design of the overall network system structure is crucial to the overall system. The main considerations for industrial Ethernet systems include: 1) Network topology analysis; 2) Data transmission analysis; 3) Performance and cabling requirements analysis; and 4) Development needs analysis. Based on the fundamental considerations for industrial network design requirements, and considering current Ethernet design methods and the application status of fieldbus, this paper designs a dual-ring redundant high-speed industrial monitoring network architecture with Ethernet as the main body. Its system structure diagram is shown in Figure 1. 3. Implementation of the Embedded Industrial Ethernet Monitoring System Hardware Platform Embedded system hardware includes a microprocessor, peripheral control circuits, read-only memory, read-write memory, and peripheral devices. This paper introduces and analyzes the independently developed embedded Ethernet monitoring system device. This device uses the 53C4510B embedded microprocessor as its core, employs the MAX1422 as a 12-bit high-speed AD converter, connects to the RTL82OIBL Ethernet physical layer interface circuit, and adds SST39VF160 and HY57V641620 as FlashROM and SDRAM units, forming the basic hardware platform. [align=center]Figure 1 Schematic diagram of dual-ring redundant high-speed Ethernet structure[/align] 3.1 Interface Circuit The PHY interface of this system is constructed using the RTL8201BL chip manufactured by Realtek. The RTL8201BL fully complies with the IEEE 802.3 physical layer protocol standard, operates on a +3.3V power supply, and supports 10/100Mbps transmission speed and half-duplex/full-duplex operation. In addition to the physical coding sublayer, physical media attachment, twisted-pair physical media sublayer, 10BASE-TX encoder/decoder, and twisted-pair media access unit, the chip also integrates filter circuitry. The RTL8201BL is directly connected to the MAC controller of the S3C4510B using the MII interface, and simultaneously connected to the RJ45 twisted-pair interface through the H1102 network isolation transformer to achieve secure isolation of the data channel. 3.2 Embedded Processor Unit Circuit The S3C4510B is the embedded processor used in the system. It is a 16/32-bit RISC architecture microprocessor with an ARM7TDMI core, designed for Ethernet applications. The ARM7TDMI is currently the most widely used high-performance core in the ARM7 series. The basic meaning of the name ARM7TDMI is: ARM7 indicates a 3V-compatible version of the ARM6 32-bit integer core; T indicates the 16-bit compressed instruction set Thumb; D indicates support for on-chip debugging; M indicates an embedded hardware multiplier; and I indicates that the embedded ICE hardware provides on-chip breakpoint and debug point support. The basic characteristics of the ARM7TDMI include: a 3-level instruction pipeline; Von Neumann architecture; embedded ICE-RT; handling of external input and output devices as memory-mapped objects; and two instruction sets. 3.3 RS-232 Serial Communication Interface The RS-232 serial interface circuit is used for peer-to-peer connection between the embedded microprocessor serial module and external serial resources, realizing the conversion between LUTTL level and RS-232 level. This paper designs and uses one RS-232 serial port circuit. Figure 2 shows the RS-232 serial interface circuit diagram. The UART0 data transmission signal UATXD0 is connected to T11 of MAX3232E. After being converted to RS-232-C level, it is connected to the RXD pin of the 9-pin connector by T10. The TXD signal of the 9-pin connector is connected to R11 of MAX3232E. After being converted to LUTTL level, it is connected to the UART0 data reception pin UARXD0 by R10. [align=center] Figure 2 RS-232 Serial Interface Circuit Diagram[/align] 3.4 Memory Unit Design The memory unit circuit consists of a large-capacity FlashROM and SDRAM. Based on the operating mechanism of embedded systems, during system startup, the Boot Loader code first copies the operating system kernel and application programs from the FlashROM into the SDRAM, performs memory relocation, and then jumps to the corresponding address in the SDRAM to execute the program. The S3C4510B supports 8-bit/16-bit/32-bit memory banks, allowing for the construction of 8-bit/16-bit/32-bit FlashROM memory systems. A wider memory data bus results in higher system performance. However, considering cost and power consumption, the design uses one SST39VF160 chip to construct a 16-bit FlashROM memory system, containing approximately 700kB of uClinux kernel and other application programs. Referring to the operating characteristics of the S3C4510B, two HY57V641620 chips are connected in parallel to construct a 32-bit SDRAM memory circuit, fully utilizing the data processing capabilities of the 32-bit CPU to meet the requirements of embedded operating systems and various complex applications. The AD acquisition unit circuit uses a 12-bit high-speed AD converter MAX1422 to construct the AD data acquisition unit. The MAX 1422 is a successive approximation parallel high-speed ADC designed by Maxim Integrated. It internally incorporates multiple frequency tracking-and-hold (T/H) fully differential input amplifier circuits, exhibiting excellent dynamic performance. The MAX 1422 has a sampling rate of 20Msps, operates at +3.3V, uses an internal reference voltage of +2.048V, and is packaged in a 48-pin TQFP. Designed for low-power applications, the MAX 1422 has a signal-to-noise ratio (SNR) of 67dB and a power consumption of 137mW at a 5MHz input signal. It exhibits even lower power consumption in low-power mode, low reference voltage mode, and shutdown mode. 4. Implementation of the Embedded Industrial Ethernet Monitoring System Software Platform The embedded industrial Ethernet monitoring system software designed in this paper includes the uCLinux embedded operating system kernel, hardware device drivers, TCP/IP communication protocol programs, and user applications. Its basic structure is shown in Figure 3. The user application mainly implements a miniature web server; the other software components are contained within a trimmed and modified uCLinux operating system. [align=center]Figure 3 Basic Structure Diagram of Embedded Industrial Ethernet Monitoring System Software[/align] 1. TCP/IP Protocol in uCLinux Operating System. As shown in Figure 4, referring to the structure of the network protocol system itself, the TCP/IP cluster in uCLinux consists of several interconnected software layers. The BSD sockets in the figure are supported by general socket software. The INET socket layer is used to manage end-to-end interconnection between IP-based TCP and UDP. TCP is a connection-oriented protocol, while UDP is a connectionless protocol. When a UDP packet is sent, uCLinux neither knows nor cares whether it successfully reaches the destination host. For TCP transmission, a connection must first be established between transmission nodes, and then the pre-ordered packets are transmitted through this connection, ensuring the correctness of the transmission. [align=center]Figure 4 Network Layer Structure of uCLinux Operating System[/align] 2. Sockets in uCLinux. Sockets are built on top of the TCP/IP protocol, and are determined by the host's IP address and port. The uCLinux system encapsulates various underlying protocols through Sockets to provide users with a general network communication programming interface. Socket abstracts and defines various network communication operations, making calling Socket as similar to operating on a regular file. It returns a corresponding Socket descriptor integer, which points to a data structure associated with that Socket. Once a Socket descriptor is established through Socket calls, the application can use other specific calls to add more detailed information to it, completing the communication establishment process. 3. Implementation of a Miniature Web Server under uCLinux. The embedded web server designed in this paper is mainly implemented by porting and modifying the Boa web server program under uCLinux. Boa is an open-source, high-performance single-task HTTP server that supports user password authentication and CGI functionality. It can provide an ideal number of simultaneous logged-in users, and its storage space requirement is appropriate, making it very suitable for embedded system applications. This system uses Boa to implement the web server program mainly by modifying the boa.conf and mime.types files. boa.conf is located in the user/boa/examples/ directory. The work done in this file includes specifying the port, the user and group attributes for the server to run, the server name, the root directory of the HTML document, the maximum number of user connections, the character encoding of the web page, and the supported file types, etc. The `mine.types` file, located in the `user/boa/examples/` directory, defines the file types supported by Boa and their classifications. The author's innovations: Based on the development trend of seamless enterprise information integration and the advanced control concept of combining 32-bit embedded processor systems with industrial Ethernet technology, this paper proposes a design scheme for a high-performance embedded industrial Ethernet monitoring system. It focuses on analyzing and implementing the hardware architecture and embedded software system of this novel embedded industrial Ethernet monitoring device. References: [1] Xiong Yuyue, Zhao Zheshen et al., Application prospects of industrial Ethernet in control system, Instrumentation Technology, 2002.3:37-39 [2] Zai Shougang, Wang Zhi, Sun Youxian et al., Discussion on the application of switches in industrial Ethernet, Chemical Automation and Instrumentation, 2003, 30(1):48-51 [3] Wang Xuelong, Embedded Linux System Design and Application, Beijing: Tsinghua University Press, 2002 [4] Ren Haibing, Chen Zhaozhang. Industrial Ethernet technology and improvement scheme, Microcomputer Information, 2007.2-3:130-132 Author Introduction: Li Wei (1958-), male, Han nationality, native of Zhumadian, Henan, associate professor, master supervisor, main research direction: database and information integration, in-memory database, embedded technology. Guo Yifan (1972-), male, Han nationality, native of Puyang City, Henan Province, Master's degree, major research direction: in-memory database, embedded technology.