HMI general knowledge for beginners is the first to understand the knowledge, the product consists of two parts, hardware and software, the hardware part of the processor, display units, input units, communication interfaces, data storage units, etc. HMI software is generally divided into two parts, that is, running in the HMI hardware in the system software and running on the PC under the Windows operating system screen configuration software. This article provides a detailed introduction to the 10 general knowledge of the human-machine interface.
Human Machine Interface (Human Machine Interaction, HMI for short)
Commonly used terms: touch screen, HMI, human machine interface
the basic functions of human-machine interface products and selection indicators
(1) Basic functions:
Equipment working status display, such as indicator, button, text, graphics, curves, etc.; data, text input operation, printout;
Production formula storage, equipment production data records;
Simple logic and numerical operations;
Can be connected to a variety of industrial control equipment networking.
(2) Selection indicators:
Display size and color, resolution;
Processor speed performance of HMI;
Input method - touch screen or membrane keyboard;
Screen storage capacity - capacity unit is byte, or bit;
Type and number of communication ports, whether to support the print function, etc..
(3) Product classification:
Primary products: membrane key input type, the display size is usually less than six inches
Intermediate products: touch-screen input type, display size is usually larger than six inches.
Advanced products: computer input type, display size is usually larger than ten inches.
The routine use of HMI steps
(1) Define the requirements of monitoring tasks and select suitable HMI products;
(2) Edit the "project file" with the screen configuration software on the PC;
(3) Test and save the edited "project file";
(4) PC connected to the HMI hardware, download the "project file" to the HMI;
(5) Connect HMI and industrial controllers (such as PLC, instrumentation, etc.) to achieve human-computer interaction.
What is the difference between a human-machine interface (HMI) and what is often referred to as a "touch screen"?
Strictly speaking, the two are fundamentally different. Because the "touch screen" is only a human-machine interface products may be used in the hardware part, is an alternative to the mouse and keyboard part of the function, installed in the front of the display of the input device.
Human-machine interface product is a kind of human-machine interaction equipment which contains hardware and software. In the industry, people often have touch input function of human-machine interface products called "touch screen", but this is not scientific.
What is the difference between HMI and configuration software?
Human-machine interface products, often called "touch screen", including HMI hardware and the corresponding special screen configuration software, in general, different manufacturers of HMI hardware to use different screen configuration software, connected to the main types of equipment is PLC.
Configuration software is running on the PC hardware platform, windows operating system under a common tool software products, and PC or industrial control machine can also be composed of HMI products; general configuration software to support a very wide range of devices, such as a variety of PLCs, PC boards, meters, inverters, modules and other devices, and because of the PC's hardware platform with strong performance (mainly reacting to speed and storage capacity), general configuration software. And because of the strong performance of the hardware platform of PC (mainly in the speed and storage capacity), the function of the general configuration software is also much stronger, which is suitable for the large-scale monitoring system.
Is there an operating system in the HMI product?
Any HMI product has a system software part, the system software runs in the processor of the HMI, which supports multi-tasking function, and there should be a small operating system in the processor to manage the operation of the system software. The high-performance HMI products based on tablet PCs generally use WinCE, Linux and other common embedded operating systems.
Can the HMI only be connected to a PLC?
Not so. HMI products are designed to solve the problem of PLC human-computer interaction, but with the development of computer technology and digital circuit technology, many industrial control devices are equipped with serial communication capabilities, so as long as there is a serial communication capabilities of industrial control equipment, such as frequency converters, DC speed controllers, temperature control instrumentation, digital acquisition module can be connected to the HMI products to realize the human-computer interaction function.
Can HMIs only be connected to other devices via standard serial communication ports?
Not so. However, with the development of computer and digital circuit technology, the interface capability of HMI products is getting stronger and stronger. In addition to the traditional serial (RS232, RS422 / RS485) communication interface, many human-machine interface products have a network port, parallel port, USB port and other data interfaces, they can be connected with a network port, parallel port, USB port and other interfaces of industrial control equipment to achieve the interaction of the equipment man-machine.
Is it true that devices with communication capabilities can always be connected to HMI products?
It should be so. Because common HMI products provide a large number of commonly used device communication drivers to choose from; in general, as long as the HMI screen configuration software to select and connect the device corresponding to the communication driver, you can complete the HMI and device communication connection. If the configuration software of the selected HMI product does not have the communication driver for the connected device, the user can inform the manufacturer of the HMI product of the type of communication port and protocol content of the connected device, and ask the HMI manufacturer to compile the communication driver for the device.
Can a PC with a display communicate directly with a PLC to fulfill the function of an HMI?
Of course. However, the PC also needs to be programmed with the appropriate configuration software in order to make the PC a real HMI product.
What is the future development trend of HMI?
With the development of digital circuits and computer technology, the future of HMI products in the function of high, medium and low division will be less and less obvious, HMI functions will be more and more rich; 5.7 inches above the HMI products will be all color display, screen life will be longer.
Due to the reduction in the cost of computer hardware, HMI products will be flat-panel PC computers for HMI hardware for high-end products, because this high-end products in the processor speed, storage capacity, the type and number of communication interfaces, networking capabilities, software resource sharing have a greater advantage in the future direction of development of HMI products. Of course, small size (display size less than 5.7 inches) HMI products, due to its advantages in size and price, with the further enhancement of its functionality (such as increasing the IO function), will be widely used in small machinery and equipment for human-computer interaction applications.
Some mechanical industries, such as machine tools, textile machinery, electronic equipment and other industries, has been developed in the country for decades, relatively speaking, belongs to a more mature industry, in the long run, these industries also exist in the demand for upgrading equipment. In this upgrading process, it is true that there will be some small, has been the use of relatively low-end products manufacturers were eliminated, but there are also many companies in the process of equipment renewal, the demand will be repositioned to look for those who are able to meet their development plans, to help them improve their own productivity of the equipment suppliers.
In view of this demand, the future of the human-machine interface will change in shape, concepts, applications and other aspects of the change, which will bring about a change in the core technology of industrial control machines. In general, the future development trend of human-machine interface is six modernization: platform embedded, brand nationalization, equipment intelligence, interface fashion, communication network and energy saving and environmental protection.