What is an HMI? What is HMI used for?

A human-machine interface or man-machine interface is a combination of software and hardware which will help the operator to communicate between systems and machines. The HMI system is inevitable in most industries the automation system is not completed without an HMI. With the help of an HMI, the operator can check the plant operation in real-time. The HMI can alarm the operator if there is any fault. So basically the HMI can be considered as the user interface in a manufacturing or process control system. The HMI will give a graphic based visualization of industrial control and monitoring system. With the help of HMI, we can increase productivity in a plant with the help of a centralized control center.

Why do we need HMI and what are the functions of HMI ?

  • It can do the visual display of the data
  • It can determine the production time, and it can find out the production faults too
  • Improved efficiency and production
  • It would sound the alarm if there is any fault
  • By using the HMI the operator can give instructions to the machine

By using HMI we can control, manage, and visualize the device process in an industry. This will allow the user to determine and respond to abnormal conditions.

What is the need for HMI in automation industries?

In an automation system, HMI is very important, by using an HMI we can visualize the representation of the control systems, and also it can give real-time data acquisition. The HMI has a centralized control center which will help the HMI to improve its efficiency. The HMI can find out if any device is not working properly or if there is any fault so it will sound an alarm, so the user can know the fault and determine where the fault is with the help of HMI. There are many electronic components in HMI and this will do the signaling and managing the automation systems and these HMI’s can transform the industrial control systems data’s into data which will be understandable to the operator. The remote access can be achieved by using the HMI and with this feature, we can securely monitor access or control all system functions. This feature will help us to pass the program to other devices

How to select an HMI for our application?

In order to select an HMI, we must consider the screen size and resolution and also its functionalities and their communication. We must consider if the design is suitable for our application.

How does an HMI work ?

The HMI consists of a monitoring screen, operating panel, and communication ports. The HMI can be integrated into our process with the help of a PC and it is done by using certain software and then the program will be transferred to the HMI and the HMI will run the program. The devices in the factory can be connected to the HMI like the machinery in a production line and also the input-output sensors and these sensors will give the data to the PLC. The monitoring screen in HMI will allow the user to interact with the HMI, the HMI has an operating panel and by this, the operator can do the required functions. The communication ports in the HMI is to program the HMI to communicate it with other devices so the devices in a factory can communicate with HMI.

What are the types of HMI?

Pushbutton replacer

This is the major type of HMI the central control panel has several buttons and these buttons are to do specific tasks and this will be very useful for industrial purposes. By the pushbutton type HMI, the productivity and efficiency of a factory can be improved. So by using this the operator can give commands to the machine to do various operations.

Data handler

This type of HMI is used for data gathering and this data will be transferred to a hard drive according to the user’s need. This type of HMI will be useful to handle applications that use a large amount of data.


This is another type of HMI and it is used with the Windows operating system. This type has great visual interaction between the human operator and the machine and mostly it would have a touch screen which would allow a graphical interface.

So all these are the types of HMI’s and the user can select it according his applications.

What is the difference between HMI and SCADA?

The SCADA is used for monitoring and controlling the entire plant and the SCADA runs on a standard computer and not in any industrial device. Mostly a SCADA system is used to handle the entire factory, the SCADA system consists of RTU, sensors, and PLC’s. The SCADA system has an HMI and by using the HMI the SCADA can communicate all the devices that it is connected to. An HMI is mostly connected to one process and it can’t handle an entire plant like the SCADA or it cannot be connected to several processes.

How can we connect an HMI with a PC?

The HMI terminals can be connected to the PC with the help of a USB or it can also be connected with the Ethernet port. In order to do the USB connection the panel view component must have a USB port to do the communication with the USB. In order to do the Ethernet connection we must first install the drivers.

What are the advantages of HMI?

Productivity can be improved

By using the HMI we can improve the efficiency of a machine which performs a task, so now with the help of HMI we can do more work in less time

Data saving

The HMI has the data saving feature, it can record the data. So all we have to do is to type the command into the HMI then it will connect to the device automatically and the data will be recorded. This data could be useful for troubleshooting and also clear the mechanical faults.

Internet of things

IOT can be considered as the collection of the devices, the HMI is also connected to the internet and because of this the remote controlling and network monitoring is possible

Data translation

The HMI would convert the data from the industrial control system into understandable data for the operator mostly it will be a visual representation and by this, the operator would be able to see the graphical representation of the system and it can be controlled.

Hardware cost can be decreased

By using the HMI we are reducing the industrial costs by eliminating or reducing the consoles, panels, cables, etc.

What are the disadvantages of HMI?

  • As we discussed earlier the HMI is connected to the internet in order to achieve the remote operation, so they can be hacked and there could be loss of data
  • Sometimes the design of HMI could create confusion between the operator and the machine and this could create major faults, and this confusion is because of the HMI design.

What are the applications of HMI?

  • In industrial automation HMI is inevitable, so it is widely used in industrial automation
  • HMI is used in vehicles, it is used in advanced driver assistant systems
  • It is used in the medical field
  • It used in manufacturing industries
  • Oil & gas
  • Power
  • Recycling
  • Food processing
  • It is used in robotics
  • Health care
  • Military and aerospace
  • Broadcast

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