Human-machine interface common sense is the first-knowledge for beginners. The product consists of hardware and software. The hardware part includes the processor, display unit, input unit, communication interface, and data storage unit. The HMI software is generally divided into It consists of two parts, the system software running on the HMI hardware and the screen configuration software running on the Windows operating system of the PC. This article gives you a detailed introduction to the 10 common knowledge of human-machine interfaces.


1. Basic functions and selection indicators of human-machine interface products

basic skills:

Equipment work status display, such as lights, buttons, text, graphics, curves, etc.;

Data, text input operations, printouts;

Production formula storage, equipment production data records;

Simple logic and numerical operations;

Can connect a variety of industrial control equipment networking.

Selection index:

Display size and color, resolution;

HMI processor speed performance;

Input method: touch screen or membrane keyboard;

The storage capacity of the screen, pay attention to the capacity unit marked by the manufacturer is byte (byte) or bit (bit);

The type and quantity of communication ports support printing.

2. Classification of human-machine interface

HMI with membrane key input, display size is less than 5.7′, screen configuration software is free, is a primary product. Such as POP-HMI small human-machine interface;

Touch screen input HMI, display size is 5.7’~12.1′, screen configuration software is free, is a mid-level product;

Based on the tablet PC computer, a variety of communication ports, high-performance HMI, display size greater than 10.4 ‘, screen configuration software charges, is a high-end products.

3. What is the difference between the human-machine interface and what people often call “touch screens”?

In a strict sense, the two are fundamentally different. Because the “touch screen” is only the hardware part that may be used in the human-machine interface products, it is an input device that replaces the functions of the mouse and keyboard and is installed at the front of the display screen. The human-machine interface product is a kind of hardware and software. Human-computer interaction equipment. In the industry, people often refer to human-machine interface products with touch input as “touch screens,” but this is unscientific.

4. What is the difference between the man-machine interface and the configuration software?

The human-machine interface products are often referred to as “touch screens” by all, and include HMI hardware and corresponding dedicated screen configuration software. Under normal circumstances, different manufacturers’ HMI hardware uses different screen configuration software, and the main equipment type to be connected is PLC. . The configuration software is a general-purpose tool software product that runs on the PC hardware platform and the windows operating system. It can also be composed of a HMI product with a PC or an industrial PC. The common configuration software supports a wide variety of devices, such as various types of devices. PLC, PC boards, meters, inverters, modules and other equipment, and because of the powerful performance of the PC’s hardware platform (mainly reflected in the speed and storage capacity), the common configuration software is also much better for large-scale monitoring System.

5. Does the man-machine interface product have an operating system?

Any human-machine interface product has a system software part. The system software runs in the HMI processor, supports multi-task processing functions, and requires a small operating system management system software to run in the processor. In the high-performance human-machine interface products based on tablet computers, general-purpose embedded operating systems such as WinCE and Linux are generally used.

6. Can only connect the PLC to the human-machine interface?

not like this. Human-machine interface products are generated to solve the problem of human-computer interaction in PLCs. However, with the development of computer technology and digital circuit technology, many industrial control devices have serial communication capabilities, so long as there is serial communication capabilities of industrial control equipment. , Such as inverters, DC governors, temperature control instruments, data acquisition module, etc. can be connected to human-machine interface products to achieve human-computer interaction.

7. Can the human-machine interface be connected to other devices only through the standard serial communication port?

In most cases this is the case. However, with the development of computer and digital circuit technology, the interface capabilities of human-machine interface products have become stronger and stronger. In addition to the traditional serial (RS232, RS422/RS485) communication interfaces, some man-machine interface products have data ports such as network ports, parallel ports, and USB ports. They can be used in industries that have interfaces such as Ethernet ports, parallel ports, and USB ports. The control devices are connected to realize the human-machine interaction of the devices.

8. Is there a device that can communicate with human-machine interface products?

It should be like this. Because common human-machine interface products provide a large number of commonly-used device communication drivers for selection; in general, as long as the communication driver corresponding to the connected device is selected in the screen configuration software of the human-machine interface, The communication connection between the HMI and the device can be completed. If there is no communication driver to connect the device in the configuration software of the selected HMI product, the user can inform the manufacturer of the HMI product about the type of the communication port and the protocol content of the device to be connected, and the HMI manufacturer is required to compile the communication driver of the device. program.

9, PC plus touch screen, can communicate directly with the PLC to complete the function of the HMI?

of course can. However, the corresponding HMI software must be compiled to make the PC a real HMI product.

10. What are the development trends of human-machine interface in the future?

With the development of digital circuits and computer technologies, the future divisions of high-, medium-, and low-level functions of human-machine interface products will become less and less obvious. The functions of HMI will become more and more abundant; HMI products of 5.7 inches or more will be all With a color display, the life of the screen will be longer. Due to the reduction in the cost of computer hardware, HMI products will use flat-panel PCs as the high-end products of HMI hardware because of the high-end products such as processor speed, storage capacity, types and quantities of communication interfaces, networking capabilities, and software resource sharing. All of them have greater advantages and are the future direction of HMI products. Of course, HMI products of small size (less than 5.7 inches in display size), due to their advantages in size and price, will be used in the man-machine interaction application of small mechanical devices as their functions are further enhanced (such as adding IO functions). Widely used.

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