Abstract: The development of library components plays a crucial role in the functionality, usability, and maintainability of industrial automation software. Currently, the library component development method provided by GE Fanuc in the iFix environment results in each screen occupying a large amount of space during storage and operation, and also presents difficulties in automatic library updates. Meanwhile, the SmartSymbol technology proposed by Wonderware in the United States lacks flexibility. This paper proposes an object-oriented library component development method in the iFix environment, successfully solving the above problems. Engineering practice has proven that this method not only unifies the style of various symbols in the human-machine interface but also improves the work efficiency of configuration personnel and project implementation personnel. Keywords: iFix software; Dynamos symbol component; VBA program Classification number: TP273+.5 Document code: B 1. Background With the development of computer application technology, industrial automation software is widely used in industrial production sites. Industrial automation software systems include real-time databases, real-time control, SCADA, communication and networking, open database interfaces, drivers for input/output devices, and human-machine interactive graphical interfaces, forming an important component of industrial automation control systems. In the human-machine interface (HMI) of industrial automation software, programmers can construct the HMI using methods such as jigsaw puzzles, building blocks, and simple connections. Symbols are reusable dynamic objects or groups of graphic objects, and several symbols constitute a library. Configuration software includes design and development libraries, such as symbols for various analog instruments, motors, and control buttons. Programmers can also design their own libraries and object symbols using basic drawing tools. Starting and stopping field equipment, valve commands, etc., are all operated through the corresponding symbols on the simulated field diagram. Simultaneously, changes in parameters under various conditions during production, as well as alarms in abnormal situations, are also fed back to the operator through the HMI software, facilitating timely action. This enables the operation and management of field equipment and controllers, which is one of the greatest advantages of configuration software. It makes programming and operation very intuitive, easily accepted by personnel with different knowledge backgrounds and skill levels. From the above analysis, it can be seen that an important criterion for evaluating the quality of configuration software is the richness of its design symbols and the intuitive representativeness of the symbols in the library. However, we should recognize that industrial automation software is a general-purpose development platform, not designed for a specific application industry, and cannot possibly include symbols from all industrial application fields. For example, the power generation industry and the petrochemical industry have different requirements for the functions and operating habits of symbols. Therefore, in actual project implementation, it is usually necessary to design and develop a set of symbols for a specific application field and the specific requirements of the customer to form a symbol library, which can be used repeatedly. This method has the following advantages: (1) Symbols encapsulate complex functions such as animation display and operation, minimizing the requirements for the programming capabilities of interface configuration personnel, engineering implementation personnel, and end users. (2) Symbols are easy to use and deploy, reducing testing, deployment, and time, and saving costs. (3) Symbols are reusable template libraries, so the entire engineering graphical interface can be standardized. Therefore, the ability of users to develop extended symbols is also a standard for evaluating automation software. 2. Implementation of Symbol Functionality in Mainstream Automation Software GE Fanuc's iFix software and Wonderware's InTouch software are currently the world's leading industrial automation software, consistently ranking among the world's most advanced technologies. These two companies have proposed their own solutions for the development and deployment of user symbols. 2.1 GE Fanuc's iFix Solution iFix is ​​the world's leading HMI/SCADA automation monitoring and configuration software, with over 300,000 software installations running globally. iFix provides a high-performance design and development platform, offering a rich set of dynamic symbols and drawing components for production processes, while also embedding VBA scripting capabilities. This platform ensures that the design process for production process screens is extremely simple and efficient. For users developing complex symbols for specific applications, GE Fanuc, through its Global Care website, provides a method to extend the functionality of dynamic symbols through VBA programming. These symbols are then stored in a symbol library directory. When needed, users simply drag and drop the symbol from the library to the required position on the screen, followed by simple configuration. Although this method solves the development and configuration of symbols through VBA embedded programming and configuration forms, it has two problems: (1) If a monitoring screen contains various types of operation and display symbols, then the screen will store configuration forms for multiple types of symbols. Usually, there are many monitoring screens in a project, and these duplicate symbols and configuration forms will occupy storage space and affect the response speed of the monitoring screen when the automation software is running. (2) If the function needs to be modified or an error needs to be found during the use of the library, it is difficult to update the symbols synchronously. Developers must open the screens that use these symbols one by one and then re-reference the symbols to make the new changes take effect. For the case where symbols are referenced in many monitoring screens, the change of symbols becomes a "nightmare" for developers. 2.2 Wonderware's InTouch software solution Wonderware's InTouch software version 9.0 features the innovative SmartSymbol technology, which integrates object-oriented technology with InTouch graphics and transforms them into reusable templates. Once a Smart Symbol instance is deployed, if a user needs to change an instance, they only need to modify the Smart Symbol template, and this change will be automatically applied to all applications and every window using the Smart Symbol instance. This makes upgrading and changing applications quick and easy. Smart Symbols represent a significant advancement in the creation, deployment, and modification of graphical elements within an application. Using the Smart Symbol Manager, application developers can create graphical templates that can be linked to Archestra Objects, local InTouch tags, and remotely referenced InTouch tags. These symbol templates are stored in the Smart Symbol Library and are instantiated by selecting and calling them into the InTouch window. Any graphic in the InTouch window can be converted into a Smart Symbol by right-clicking. Furthermore, the Smart Symbol Library can be exported to other applications and factories, thus standardizing the company's graphical interface. However, due to differences in software architecture compared to GE iFix, the user programming support in the InTouch software's SmartSymbol is not as flexible as in the iFix software, which to some extent limits the application of SmartSymbol in more complex engineering applications. 2.3 Object-Oriented Symbol Component Development Method By summarizing and analyzing the development methods and characteristics of symbols in iFix and InTouch software, we propose an object-oriented symbol component development method based on the iFix development platform. By separating the symbol elements and configuration window code, we successfully solve the difficulties in development and make the developed symbols have the advantages of both iFix and InTouch environments while overcoming their disadvantages. The specific development solution is as follows: (1) Use the provided drawing tools to draw the appearance of the symbol to be designed. At this time, the symbol does not have any dynamic display and will not respond to any operation to trigger events. In the process of symbol appearance design, pay attention to the naming rules that each element and symbol component in the symbol should conform to. It should be clear and concise, and the system default naming should not be used. For example, there are many types of symbol components used for numerical display in industrial production processes. Some only have display, some need to display and also have alarm prompt functions, and some also need to have annotations and descriptions. Therefore, different types of numerical displays can be named DigiDispA1, DigiDispB1, DigiDispC1, etc. The first step to success is to design the appearance of the symbols that conform to the actual usage habits on site and to have good naming habits. (2) The design of the symbol configuration form is the key to the programmer to implement the design of the symbol function. All dynamic display functions, such as the function that the displayed value changes with the change of production process parameters, the function that the color changes when the value exceeds a certain range to attract attention, and the pop-up of the symbol operation form after the mouse click, are all implemented here. It encapsulates the attributes, methods and message responses of the symbols. The source code of the initialization of the symbols and some attribute settings and readings used are shown in Figure 1 below. It should be noted that the symbol configuration form should be placed in the global project, such as: project user or project plugandsolve, so that all project screen files can be accessed. However, the solution provided by iFix is ​​to place the configuration in a single screen, which causes problems with screen size and updates. Placing it in the global project can avoid this situation. Figure 1: Example of source code development in the configuration form (3) Since the configuration form is placed in the global project, response code should be added when calling the configuration form and responding to the symbol event. The main process involves calling and initializing the symbol using the `InitializeDynamo` method based on the symbol component name. Through these three basic development steps, combined with the designer's industry background knowledge and programming skills, a beautiful and professional set of symbols is developed. The developed symbol components depart from the built-in configuration method of iFix software, replacing it with user-customized forms tailored to the actual project needs. Symbols can be simple animations or complex, powerful functions, such as symbols that respond to mouse clicks and pop up corresponding operation windows at runtime. The configuration process automatically completes the necessary VBA scripts, eliminating the need for professionals to write corresponding VBA code. Figure 2 shows a developed symbol library and an example of a flowchart interface developed using symbols from the library. Figure 2: Symbol Library and Symbol Configuration Forms and a Flowchart Interface Developed Using Symbols from the Library. Although developing symbols requires a significant initial investment of time and effort, it is extremely convenient for users. Complex tasks that previously required automation software configuration engineers to draw diagrams, link links, and write scripts can now be completed by ordinary engineers. These improvements are highly beneficial for reducing personnel costs, improving operational efficiency, and standardizing design during project implementation. 3. Conclusion The method of separating symbol elements and configuration forms from code fully utilizes the flexible and convenient programming environment of iFix, realizing a complete symbol design process. This addresses the shortcomings of mainstream industrial automation software in implementing symbol functions and meets the needs of practical engineering applications. Engineering practice has proven that this method not only unifies the style of various symbols throughout the entire engineering machine interface but also improves the automation level of the software, freeing on-site debugging personnel from tedious programming and increasing the work efficiency of configuration and project implementation personnel. References: 1. GE Fanuc, iFix Electronic Book, GE Fanuc, 2005 2. GE Fanuc, iFix Database Access Toolkit Help, GE Fanuc, 2005 3. Eric Brierley, Anthony Prince, David Rinaldi, Visual Basic 6 Developer's Guide, Machinery Industry Press, 2001 4. Renee Brandt, InTouch 9.0 SmartSymbol and IOSetRemote References, Wonderware Corporation, 2006