You may be unfamiliar with the term "HMI", but you've probably interacted with it frequently in daily life. So what exactly is HMI?
HMI (Human-Machine Interface) is the critical bridge for information interaction between humans and machine equipment. In industrial environments, HMI plays a vital role in controlling equipment and monitoring its operational status in real-time.
A familiar example of HMI is the ATM machine—through its screen and buttons, users can complete operations such as withdrawals and deposits.
In the pursuit of automation in industrial fields, HMI is almost indispensable. It typically appears in the form of display screens, similar to computer monitors, and increasingly uses touch technology. Operators or maintenance personnel use these interfaces to manage and observe equipment operation.
Industrial HMI can display rich information, such as temperature, pressure, process step progress, material counts, and even precisely show liquid levels in containers or specific positions of equipment. The strength of modern HMI is that it can integrate and display data streams from multiple devices on a single screen, although specific implementations may be limited by particular software and hardware platforms.
Benefits of Industrial HMI
Many HMIs can directly connect to Programmable Logic Controllers (PLCs) and display PLC data in real-time on screens, greatly facilitating troubleshooting. This is much more efficient than having to connect a computer or laptop each time.
Modern HMI enables factories and industrial facilities to centrally manage multiple machines or equipment. Even small manufacturing plants can achieve overall monitoring of all factory equipment through a single HMI interface located in a central control room.
Take water supply and wastewater treatment facilities as examples—they have long combined HMI with PLC technology to remotely monitor the status of critical equipment such as water pumps, whether located at the plant or distributed sites.
Now that we understand that HMI is an operation panel and monitoring screen, how does it actually connect to machines and perform functions? The key lies in programming and communication.
Dedicated Software Programming
HMI operation relies on specialized software, with different HMI brands using their own supporting software. Engineers use this software to design what users see on the screen (graphical interface), define the data points that need monitoring, and design "virtual buttons" for operational control.
Interface Design Example
For example, engineers can design a graphic representing a large storage tank on the HMI screen and display its liquid level in real-time. Next to it, they might design an icon representing a water pump and "Start" and "Stop" buttons to control that pump. Users can click these buttons to remotely operate the water pump.
Behind the Scenes: Logical Connections
However, this isn't as simple as placing graphics and buttons on the screen. HMI programmers must precisely map each data indicator (like liquid level) and each operation button (like start/stop buttons) to specific register addresses within the PLC.
Compatibility & Communication Protocols
This brings us to a key point: HMI and PLC must be compatible and able to communicate. They interact by following specific "protocols". Common industrial communication protocols include:
- Modbus
- Ethernet/IP
- PROFIBUS
- PROFINET
- CANopen
- DeviceNet
These protocols establish communication networks between industrial equipment, conceptually similar to local area networks connecting computers, printers, and other devices in homes or offices.
Collaborative Operation
As long as HMI and PLC can successfully establish communication, the instructions and data programmed by engineers in the HMI can be used to monitor the PLC's operational status and control equipment functions through the PLC.
Summary
Today we've explored the fundamentals of HMI (Human-Machine Interface). As a "window" and "control panel" for machines, it allows operators to monitor equipment status and issue control commands. Engineers use specialized software to program HMI, giving it specific monitoring and control capabilities. HMI works in close collaboration with PLCs to jointly manage and control machines, which requires that the two must be compatible and "speak the same language"—that is, use the same communication protocol. This protocol is essentially a dedicated data network built in industrial environments.
Company Introduction
Jingcai Intelligence is a rapidly growing technology enterprise integrating R&D, production, and sales. We specialize in providing Human-Machine Interaction Display Solutions and USART-HMI Display Modules.
1.28"-21.5"
Display Size Range
200+
Industry Applications
Core Technology
Our self-developed GUI development software Guition® enables rapid UI interface development and efficient HMI implementation.
Product Portfolio
Comprehensive display solutions covering sizes from 1.28" to 21.5", suitable for various application scenarios.
Customization Capabilities
Full-spectrum customization services including hardware structure, UI design, and software functionality.
Industry Applications
Our serial port smart screens are widely used in advanced manufacturing and smart technology fields:
3D Printing Equipment
Air Quality Monitors
Medical Devices
EV Charging Stations
Smart Home Systems
Intelligent Warehousing
Industrial Automation
Security Systems
AI Devices
Commercial Kitchen
Audio Equipment
Automotive Dashboards
Professional Commitment
Premium Quality
User-Friendly
Superior Experience
Value-Added Products
Efficient Support
Expert Team
We possess first-class R&D capabilities and have earned widespread recognition through excellent products and attentive service. Our core mission is to "Create Practical Value for Clients".
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