Human-machine interfaces (HMIs), whether for field controllers or higher-level monitoring and management, are closely related, as they monitor and manage the same field equipment. I. Introduction Modern automatic control system designs are almost entirely based on graphical user interfaces (GUIs). Process flows, system performance indicators, system characteristic parameters, operating status, development trends, historical evolution, and management implementation can all be realistically and intuitively displayed to operators and management decision-makers in real time. Because graphical information contains far more information than other forms such as text, symbols, and sound, it is an effective means of human-machine interaction. Therefore, the design of HMIs plays a crucial role in automatic control systems. The development of industrial automation configuration software has provided powerful tools for the creation and connection of these interfaces, greatly facilitating the realization of system monitoring, control, and management functions. This article discusses the design of graphical user interfaces in automatic control systems from an application perspective. II. Basic Requirements for Graphical User Interface Monitoring Platforms Automatic control system monitoring platforms should be able to conveniently and quickly meet the following basic requirements through graphical interfaces: 1. They should be able to meet both the coordinated control of the overall system operation and the individual control of individual devices, while also allowing for individual field control; 2. 1. Data collected on-site can be processed and responded to within a limited time, and information release can be controlled accurately and promptly; 2. Control laws and parameters can be conveniently adjusted and set online through the screen; 3. The human-machine interface can intuitively see the operating status of the on-site system and equipment, and fault information can be transmitted to the monitoring operation platform in a timely manner. The operation platform can remind operators in the form of sound, light, and images; 4. On-site production and equipment information can be classified and managed; 5. Data management information output and printing are supported; 6. When the monitoring operation platform is offline and disconnected from monitoring for special reasons, the on-site control system can still operate in conjunction; 7. Redundancy and fault-tolerant control requirements can be met. When the monitoring software cannot be used normally due to (such as sudden failure), there should be a backup that can be put into use in a timely manner. When abnormal operation (such as misoperation) or accidental triggering of control is performed, it has a certain degree of fault tolerance and will not blindly respond; 8. It has safety protection measures for override control. For example, when the monitoring system encounters abnormal signals such as accident alarms, deviation exceeding limits, and faults, and the operator cannot give timely control or take measures for other reasons, the entire operating system will switch to some pre-set safety states. III. Graphical User Interface Design (I) Human-Machine Interface (HMI) The human-machine interface refers to the communication medium or means between human users and computer systems. It is the supporting software and hardware for two-way information exchange between humans and machines. After the 1970s, the so-called WIMP interface gradually formed, which is a human-machine interface technology based on windows, icons, menus, and pointing devices. The current multimedia interface is a further extension of WIMP. The multimedia interface has improved the way interface information is presented. Virtual reality technology, multimedia, and visualization have put forward high-efficiency, three-dimensional, and imprecise requirements for the human-machine interface interaction of computer systems. That is, the human-machine interface has the ability to perform three-dimensional direct operation naturally, can support time-varying media, and realize three-dimensional, imprecise, and implicit human-machine interaction. (II) Graphical User Interface Design In general, the field controller is supervised by professional technicians and equipment maintenance personnel. They are very concerned about the amount and type of real-time data information reflected on the human-machine interface, as well as the equipment operating status. They hope that the control operation can be simple, fast, timely, accurate, and convenient. For sudden failure events, they require the ability to quickly switch equipment and clear alarms. Therefore, there are some special requirements and design principles to follow when designing human-machine interfaces for industrial field control. 1. Basic requirements of the field bottom layer for graphical user interface (1) Simplify the operation of the user interface. Short operation commands facilitate quick input and execution of control information. Simplify the human-machine interaction dialogue steps, such as defaulting some commonly used parameter values ​​during normal operation. According to the operation and running rules of the equipment, input each group of control parameters in a bundled manner. If necessary, shield and bundle some parameter transmission and dialogue details that are carried out during operation, and these parameters and dialogue details can be unpacked or examined in detail according to certain steps during maintenance or diagnosis. (2) Try to reflect the important parameter information of the controlled equipment object directly on the main interface, and arrange their display positions on the interface according to the frequency of human-machine interaction and their importance requirements. The important parameters of the dynamic change of the object and the data information collected in real time should be displayed on the interface in the form of charts to facilitate intuitive real-time monitoring and control. (3) Reduce and avoid secondary menu operations and controls. The real-time requirements of field control are very high, and secondary menus are not conducive to improving the system response speed. When the on-site operators are able and can easily accept it, it is appropriate to reduce the number and size of icons on the interface in exchange for the possibility and number of parameters of the directly monitored objects. (4) For setting the priority of interface display or prompts for emergencies, it is advisable to adopt the interactive mode of pop-up dialog window interface triggered by the event. The setting of event resolution priority is combined with the requirements and order of process importance. (5) Coordinate the display mode of the operation interface. In the actual operation of equipment, a common contradiction is that skilled operators (such as on-site operators) want to use multiple control language input methods for speed and timeliness, while other technicians (such as supervisors, maintenance personnel or on-site novices) want to use more icon dialogue methods for intuitive convenience and to reduce the need to memorize instructions. Therefore, scientifically and reasonably coordinating the cooperation of the above two interface operation methods is a very important link. When necessary, it is necessary to design a dual user interface with icon dialogue operation as the main interaction interface and control command statement input as the main interaction interface. Users can switch operations as needed. (6) Set up safety operation protection measures. The field controller is directly facing production and equipment. Usually, in order to start up, control and run quickly, the control password is short and the access permissions and passwords are few. Therefore, it is easy to cause misoperation, which directly endangers production safety and reliability. Therefore, the interlocking control and protection diagnostic input should be reflected in the design of the interactive interface. For control information input that does not conform to normal operation or logical sequence, prompts or warnings should be given, and execution should be rejected or wait for further confirmation according to classification and level. (7) Set up system safety operation protection measures. In field control, the safety protection measures of override control should be highlighted. According to the cause and category of the accident, the logic operations such as automatic to manual, priority reduction, prohibition of increase and prohibition of reduction should be performed to switch the control system to some pre-set safety states. 2. Human-machine interface design principles In addition to human-machine interaction with professional engineers and system maintenance engineers, the monitoring system also needs to interact with non-professional management personnel, such as production decision-makers, planners and sales personnel. They need to understand the on-site production situation through the monitoring computer interface and issue some control information to guide the operation of the on-site system. Therefore, they have high requirements for the intuitiveness and friendliness of the human-machine interface. The human-machine interface design should consider the following principles. (1) Sequence principle. That is, design the monitoring and management human-machine dialogue main interface and its secondary interfaces according to the order of event processing, access and viewing (such as from whole to single item, from large to small, from upper layer to lower layer, etc.) and control process flow. (2) Functional principle. That is, design the human-machine interaction interface with multi-level menus, layered prompts and windows with multiple dialogue bars, etc., according to the specific functional requirements of the object application environment and occasion, the control type of various subsystems, the parallel processing requirements of the same interface of different management objects, and the simultaneous requirements of multiple dialogue interactions, so that users can easily distinguish and master the usage rules and characteristics of the interaction interface, and improve its friendliness and ease of operation. (3) Frequency principle. That is, design the hierarchical order of the human-machine interface and the display position of the dialogue window menu according to the high and low dialogue interaction frequency of the management object, so as to increase the monitoring and access dialogue frequency. (4) Importance principle. That is, design the position and prominence of the main and secondary menus and dialogue windows of the human-machine interface according to the importance and global level of the management object in the control system, so as to help managers grasp the main and secondary aspects of the control system, implement the order of control decisions, and achieve optimal scheduling and management. (5) Object-oriented principle. In other words, a user-friendly human-machine interface (HMI) should be designed according to the operator's identity and job nature. Pop-up windows should be used to display prompts, guidance, and help information based on their work needs, thereby improving user interaction and efficiency. IV. Conclusion HMIs, whether for field controllers or higher-level monitoring and management, are closely related. They monitor and manage the same field devices, and therefore many field device parameters are shared and transferred between them. Various industrial control configuration software and programming tools provide powerful support for creating sophisticated HMIs, especially Wonderware's Factory Suite industrial automation software, whose superiority becomes more apparent with larger and more complex systems.