Connected to the programmable logic controller (PLC), frequency converter, DC governor, instrumentation and other industrial control equipment, the use of display screen, through the input unit (such as touch screen, keyboard, mouse, etc.) to write the work parameters or input operating commands, to achieve the information interaction between man and machine digital equipment, composed of two parts: hardware and software.
hmi is the abbreviation of English Human-MachineInterface.
Industrial advantages of human-machine interface products
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For maintenance personnel, many HMIs can also be connected to PLCs and display their data on the screen to carry out troubleshooting. This saves valuable time compared to connecting a computer or laptop each time.
Another benefit of having a modern HMI is that factories and other industrial locations can monitor and control multiple machines or other equipment.
A small manufacturing plant may even be able to monitor the entire plant from one centrally located HMI.
For years, water systems and wastewater treatment facilities have used HMIs in conjunction with PLCs. The ability to remotely monitor locations such as pumps as well as equipment within the plant.
By now, you probably understand that HMIs are operator panels and monitor screens. But how do HMIs actually connect to machines for control and monitoring?
Let's take a look.
First, HMIs use specialized software that engineers can program. Different brands of HMI use different software.
Engineers can design the software on the screen to actually see the content, you can monitor the data on the screen, you can design the "button" to achieve operational control.
For example, the HMI may show a large tank on the screen, and display the level. Next to the tank is a pump, used to control the liquid level.
The HMI may also display a start and stop button on the screen next to the pump, which can be used.
This button enables turning the pump on and off.
However, this is not as simple as placing a button on the screen or placing a tank with a level on the screen.
The HMI programmer must program each indicator and button into a designated register address on the PLC.
This raises another point, which is that the HMI and PLC need to be compatible. This means that they need to enable interaction. They perform operations according to what is known as a protocol. Different companies use different protocols.
Common protocols are Modbus, Ethernet/IP and Profibus, all of which are industrial communication networks, kind of like the network you have in your house where multiple computers, TVs or other devices are connected to each other.
As long as the PLC and the HMI can interact, you can use the command data programmed in the HMI to monitor and control PLC functions.
Basic Functions of HMI Products
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Basic Functions.
Equipment working status display, such as indicators, buttons, text, graphics, curves and so on.
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 network.
Human-machine interface product classification
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Membrane key input HMI, display size less than 5.7, screen configuration software free, is a primary product.
Such as POP-HMI small HMI: touch-screen input HMI, display size of 5.7-12.1, screen configuration software free of charge, is an intermediate product.
Based on the flat 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.