HMI is short for Human Machine Interface. We use HMIs in industry to control and monitor machines. A very common HMI that you all encounter on a regular basis would be an ATM machine. The screen and pushbuttons allow you to operate the machine to dispense a certain amount of money, or to deposit money.
It would be hard to have a good automated process in industry without an HMI. Many times an HMI will be in the form of a screen, kind of like a computer screen, and more times than not, they are touch screen.
An operator or maintenance personnel can operate and monitor the machine from the HMI.
They may include information like temperature, pressure, process steps, and material counts. They can also show very precise levels in tanks and exact positioning of machines.
Where machine information used to be viewed on multiple indicators can now be viewed on one screen. The possibilities are only limited to the software and hardware used.
For maintenance personnel, many HMIs can also connect to PLC logic and display it on the screen for troubleshooting purposes. This can save valuable time compared to connecting a computer or laptop every time.
Another benefit of having a modern HMI is the fact that plants and other industrial sites can monitor and control multiple machines or other equipment. A small manufacturing facility could even monitor the entire plant on one centrally located HMI.
Water and wastewater facilities have utilized this for years by coupling an HMI with a PLC. They are able to monitor remote locations, like water pumps, as well as equipment inside the plant.
You probably get the idea now that an HMI is the operating panel and monitoring screen. But how does the HMI actually connect to the machine to be able to control and monitor it? Letâ€™s take a look.
First, HMIs use special software so engineers can program them correctly. Different brands of panels use different software accordingly
The software allows the engineer to design what the operator will actually see on the screen, what they can monitor on the screen, what â€œbuttonsâ€ can be pushed, and how the operator can manipulate the machine.