The relationship between man-machine interface and PLC control system

In addition to communicating and sharing information with plc, touch screen can also be connected with a variety of other peripheral devices. It may have its own electrical contacts; it can output audio signals; it can be connected to a bar code scanner to read the bar code directly; it can also generate reports and print out. Because it is a computer, the realization of multimedia functions is also a matter of responsibility. Of course, it may not be necessary, and additional costs may be needed to do so. For example, expand memory.

With the help of network functions, the present control system can form a large system of any size that is not limited by space. It is impossible for us to study all kinds of information here. Let's return to the topic of human-machine interface. Man-machine interface is a tool that can facilitate the exchange of information between man and machine, which is the "translation" between man and machine. The information in man-machine interface reflects the relationship between owner and control system.

I. The relationship between division of labour and cooperation
Man-machine interface is an indispensable part of the system. They can only be the relationship of division of labor and cooperation, each performing its own duties.

II. The Relation between Leadership and Being Leaded
Human-machine interface actually represents human requirements.Therefore, it has established its dominant position. All the work is done under the organization, management and monitoring of the information it conveys. The specific way to accomplish this kind of leadership or organization is to make some choices through the man-machine interface and change some data or signs.

III. Time Series and Conflicts of Control Instructions
Since the normal work of the system, including the content displayed on the touch screen, is automatically completed in accordance with a pre-programmed program. But there are two exceptions: first, when there is an unexpected emergency in the system, it must be given priority. At this time, the man-machine interface must convey the latest information at the same time, and wait for instructions for the next step. (2) For various reasons, operators require immediate intervention in the current process. Man-machine interface must provide this possibility at any time and feedback the effect of intervention immediately.
Nevertheless, don't forget that PLC and GOT are actually two computers running independently, and the means to complete or embody the operator's intention is only to make some choice, or to change some data or signs. Its effect should ultimately be reflected in the shared data and information, rather than direct intervention. Therefore, the priority of GOT command must be guaranteed in the design, that is, to maintain the relationship between the leader and the leader, and internal conflicts must not occur. The coordination between PLC and GOT software should be carefully considered first.