Graphical User Interface Design Analysis in Automatic Control System

I. Introduction

The design of modern automatic control systems is almost always based on the Object screen. Process flow, system performance indicators, system characteristic parameters, operation status, development trend, historical evolution, management implementation, etc. can all be vividly displayed in operation management decisions in real time through the screen. In front of the person. Because the amount of information contained in the graphic information is much larger than other forms such as words, symbols, sounds, etc., it is an effective means for human-computer interaction. Therefore, the design of the human-computer interaction screen occupies an important position in the automatic control system. The development of industrial automation configuration software has provided powerful tools for the production and connection of these screens, bringing great convenience to the functions of monitoring, control and management of the system. This article discusses the application of graphic user interface design in automatic control system from the perspective of application.

Second, the basic requirements for the screen monitoring platform

The automatic control system monitoring platform should be able to easily and quickly reach the following basic requirements through the screen:

1. It can not only meet the linkage control of the overall operation of the system and the individual control of the single equipment, but also allow single-action control at the scene.

2. The data collected at the site can be processed and responded within a limited time, and control information release accurately and timely;

3. Control laws and parameters can be conveniently adjusted and set online via the screen.

4. The man-machine interface can intuitively see the operating status of the on-site system and equipment. The failure information can be timely transmitted to the monitoring and operating platform. The operation platform can remind the operator in the form of sound, light and images.

5. Can manage the on-site production and equipment information classification;

6. Supports output printing of data management information;

7. When the monitoring and operation platform is offlined and monitored due to special reasons, the on-site control system can still operate in linkage.

8. Can meet the redundancy and fault-tolerant control requirements. When monitoring software (such as sudden failure, etc.) cannot be used normally, backups should be put into use immediately. When performing abnormal operations (such as misoperations) or accidentally triggering control, it has certain fault tolerance and does not respond blindly;

9. With overclocking safety protection measures. For example, when the monitoring system encounters abnormal signals such as accident alarms, deviations exceeding limits, and faults, and the operator is unable to give timely control or take measures due to other reasons, the entire operating system is converted to some pre-set safety conditions.

Third, the graphical user interface design

(1) Man-machine interface

Human-machine interface refers to the communication media or means between human users and computer systems. It is the supporting software and hardware for human-computer two-way information exchange. After the 1970s, the so-called WIMP interface was gradually formed, namely the human-machine interface technology based on windows, icons, menus and pointing devices. The current multimedia interface (Multimedia Interface) is a further extension of WIMP style. The multimedia interface has been improved in the presentation of interface information. Virtual reality technology, multimedia and visualization have provided efficient, three-dimensional, and non-human interface interactions for computer systems. The precise requirement, that is, the man-machine interface has the ability to naturally perform three-dimensional direct operations, can support time-varying media, and achieve three-dimensional, inaccurate, and implicit human-computer interaction.

(B) Graphical User Interface Design

Under normal circumstances, on-site controllers are supervised by professional technicians and equipment maintenance personnel. They are concerned about the amount of real-time data and the types of information that can be reflected on the man-machine interface, and the operating conditions of the equipment. It is hoped that the control operation can be simple. It is quick, timely, accurate and convenient. For emergencies, it is required to quickly switch devices and remove alarms. Therefore, when designing the man-machine interface for industrial floor control, there are some special requirements and design principles that should be followed.

1. The basic requirements for the graphical user interface at the ground floor

(1) Simplify the user interface operation. Short operating commands facilitate quick input and execution of control information. Simplify human-computer interaction dialog steps, such as defaulting some commonly used parameter values ​​during normal operation. According to the operation and operation rules of the equipment, bundled input each group of control parameters. If necessary, mask and bundle some of the parameter transfer and dialog details that are performed during the operation, and in the course of maintenance or diagnosis, the parameters and dialog details can be resolved or scrutinized according to certain steps.

(2) As far as possible, the important parameter information of the controlled device object is directly reflected on the main interface, and their display positions on the interface are arranged according to the frequency of human-computer interaction and its importance requirements. The dynamic change of the object's important parameters and the real-time collected data information should be displayed on the interface in the form of a chart to facilitate intuitive and real-time monitoring and control.

(3) Reduce and avoid secondary menu operations and controls. The real-time requirements of on-site control are very high, and the secondary menu is not conducive to improving the system response speed. In the case where the on-site operator is able and relatively easy to accept, it is appropriate to exchange the number and size of the icons on the interface in exchange for the possibility and quantity of the parameters of the directly monitored object.

(4) For emergencies setting interface display or prompting priority, the interactive mode of the event-inspired pop-up dialog window interface should be adopted. The setting of the event resolution priority should be combined with the process importance requirement and sequence.

(5) Coordinate the display mode of the operation interface. In the actual equipment operation process, there is usually a contradiction situation: skilled operators (such as job operators) want to use a variety of control language input methods, in order to be quick and timely, and other technical personnel (such as supervisors, Maintenance staff or newcomers to the job) want to use more iconic dialogues for intuitive convenience and less memory instructions. Therefore, scientific and reasonable coordination of the cooperation of the above two interface operation modes is a very important link. If necessary, a dual user interface mainly consisting of an interactive interface based on icon dialogue operations and an interactive interface based on the input of control command statements should be designed. Users can switch as needed.

(6) Set safe operation protection measures. The field controller is directly oriented to the production and equipment. Usually, in order to start, control and run quickly, the set control password is short, and the access authority and password are less. Therefore, the controller is prone to misoperation and directly endangers production safety and reliability. For this reason, chain control and protection diagnosis input should be importantly reflected in the design of the interactive interface. For the input of the control information that does not meet the normal operation or logical sequence, prompt or warning information is given, and the execution is rejected if the classification and level refuse execution or wait for further confirmation.

(7) Set up system safety operation protection measures. In field control, the safety protection measures for overriding control shall be highlighted, and the logic operations such as automatic cut manual, priority reduction, prohibition increase, and prohibition reduction shall be performed according to the cause and category of the accident, and the control system shall be converted to some preset values. Safe state.

2. Human-machine interface design principles

In addition to the human-machine interaction with professional engineers and system maintenance engineers, the monitoring system also requires human-machine interaction with non-specialized management personnel. For example, production decisions, plans, and sales personnel need to understand the on-site production status through the monitoring computer interface and issue some controls. Information to guide the on-site system operation. Therefore, they have high requirements for the intuitiveness and friendliness of the human-machine interface. The following principles should be taken into account in the design of the human-machine interface.

(1) The principle of order. That is, the main interface of monitoring and man-machine dialogue and its secondary interface are designed according to the order of processing events, the order of visits (from the whole to the individual, from big to small, from the upper to the lower, etc.) and the control process flow.

(2) Functional principle. That is, according to the specific application function requirements of the object application environment and occasions, the control requirements of various subsystems, the same interface parallel processing requirements of different management objects, and the simultaneity requirements of multiple dialogue interactions, etc., the design of sub-functions distinguishes between multi-level menus and hierarchical prompts. The human-computer interaction interface, such as information and multiple windows in the dialog box, makes it easy for the user to distinguish and grasp the usage rules and characteristics of the interactive interface, and improve the friendliness and ease of operation.

(3) Frequency principle. That is, the hierarchical order of the human-machine interface and the display position of the dialogue window menu are designed according to the frequency of the interactive interaction of the management object, and the frequency of monitoring and access to the dialogue is improved.

(4) The principle of importance. That is, according to the importance and overall level of the management object in the control system, the position and salience of the primary and secondary menus and dialog windows of the man-machine interface are designed, which helps the management personnel to grasp the primary and secondary control system well and to implement the control. The order of decisions, to achieve optimal scheduling and management.

(5) The object-oriented principle. That is, in accordance with the identity characteristics of the operator and the nature of the work, an adaptive and friendly man-machine interface is designed. According to their working needs, prompting, guiding, and helping information should be displayed in a pop-up window, thereby improving the user's level of interaction and efficiency.

Fourth, the conclusion

Human-computer interaction interface, whether it is for the site controller or for superior monitoring management, both are closely intrinsically linked, they monitor and manage the field device object is the same, so many field device parameters are shared between them And pass on each other. A variety of industrial control configuration software and programming tools provide a powerful support tool for the production of exquisite human-computer interaction interface, especially the United States Wonderware Industrial Automation Suite suite software, the system is more complex and more able to reflect its superiority.