What Is An HMI And What Is The Difference Between An HMI And A Touch Screen

What is the difference between a human-machine interface and what is often referred to as a "touch screen"? Technically speaking, there is a fundamental difference between the two. Because the "touch screen" is only the hardware part of the HMI product that may be used, it is a replacement for the mouse and keyboard part of the function, installed in the front of the display input device; while the HMI product is a human-computer interaction device containing hardware and software. In industry, people often refer to human-machine interface products with touch input functions as "touch screens", but this is not scientific. 
 Touch screen is the common name for "human-machine interface with touch function"! A true touch screen is "a piece of transparent glass that can be operated by hand".

1, human-machine interface and people often say "touch screen" what is the difference?

    In a strict sense, there is a fundamental difference between the two. Because the "touch screen" is only part of the hardware that may be used in the human-machine interface products, is an alternative to the mouse and keyboard part of the function, installed in the front of the display input device; and the human-machine interface products are a kind of human-computer interaction equipment containing hardware and software. In industry, people often touch the input function of the human-machine interface products called "touch screen", but this is not scientific.

 2、What is the difference between HMI and configuration software?

    HMI products, often referred to as "touch screen", including HMI hardware and the corresponding special screen configuration software, in general, different manufacturers of HMI hardware using different screen configuration software, connecting the main types of equipment is PLC. The common configuration software supports a wide range of devices, such as PLCs, PC boards, meters, inverters, modules and other devices. Large-scale monitoring systems.

 3. Is there an operating system in the HMI product?

    Any HMI products have a system software part, the system software runs in the HMI processor, supporting multi-tasking functions, the processor needs a small operating system to manage the operation of the system software. High-performance HMI products based on flat-panel computers generally use WinCE, Linux and other common embedded operating systems. 

 4、Can the HMI only be connected to a PLC?

    Not so. HMI products are designed to solve the problem of human-machine interaction with PLC, but with the development of computer technology and digital circuit technology, many industrial control devices have serial communication capabilities, so as long as there is serial communication capabilities of industrial control equipment, such as frequency converters, DC governors, temperature control meters, digital pick-up modules, etc. can be connected to HMI products to achieve human-machine interaction functions.
   
  5、Can the HMI only be connected to other devices 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 capability of HMI products is becoming stronger and stronger. In addition to the traditional serial (RS232, RS422/RS485) communication interface, some HMI products have a network port, parallel port, USB port and other data interfaces, they can be connected to industrial control equipment with a network port, parallel port, USB port and other interfaces to achieve human-machine interaction of equipment.
   
  6、Is it true that equipment with communication functions can always be connected to HMI products?
  This should be the case. Generally, as long as the communication driver corresponding to the connected device is selected in the screen configuration software of the HMI, the communication connection between the HMI and the device can be completed. If the selected HMI product configuration software does not have a communication driver for the connected device, the user can inform the manufacturer of the HMI product of the communication port type and protocol content of the connected device, and ask the HMI manufacturer to prepare the communication driver for the device.

   
 7、Can a PC with a touch screen communicate directly with a PLC to complete the functions of an HMI?

    Of course you can. However, the corresponding HMI software has to be prepared in order to make the PC a real HMI product.

  8、What is the future development trend of HMI?

    With the development of digital circuitry and computer technology, the division between high, medium and low in the functions of future HMI products will become less and less obvious, and the functions of HMI will become richer and richer; all HMI products above 5.7 inches will be colour displays, and the life of the screen will be longer. As the cost of computer hardware decreases, HMI products will be mainly high-end products with flat PC computers as the HMI hardware, because such high-end products have greater advantages in processor speed, storage capacity, communication interface types and numbers, networking capability and software resource sharing, which are the future development direction of HMI products. Of course, small size (display size less than 5.7") HMI products, due to their advantages in size and price, will be widely used in the human-machine interaction applications of small mechanical equipment as their functions are further enhanced (such as adding IO functions).