Like any other machine, an HMI can break, and before you can fix it, you need to find out what the problem is. T2Industrial has a team of industrial control experts and with their help, we have identified 5 common HMI failures that users encounter.
What Is An HMI?
The complex set of machines that make up an automated system requires accessible connections between the machine and the person operating it. HMI stands for human-machine interface. This interface is usually a screen or panel through which a person can connect to any device, machine, or system. A human-machine interface (HMI) can be anything that lets you interact with electronics, including your smartphone. Today’s automated facilities increasingly use HMIs in addition to various visual control panels.
Although other terms may be used to refer to this technology, such as operator interface terminal (OIT), local operator interface (LOI), and man-machine interface (MMI), HMI is the most common. It is sometimes used to refer to a graphical user interface (GUI), but these are not the same thing. A graphical user interface allows the user to navigate the screen using images or icons rather than text or commands. It has similar capabilities to an HMI but is generally used to enable visualization within the HMI. An HMI can take the form of a tablet, computer monitor, or screen built into the machine, but all of these give operators insight into machine performance and progress.
Industrial HMIs are typically used for auditing purposes, including monitoring inputs and outputs, tracking key performance indicators, tracking production statistics, and providing visual representations of key data. In factories, HMI can be used to monitor pump functions, control safety systems, manage production lines or maintain optimal working conditions for personnel. Most home HMI functions are basic versions, such as controlling your washing machine or air conditioner, and your smart home can be completely controlled with a single tablet.
HMI Health
The HMI constantly gives feedback on its status and provides a lot of information about possible errors in the future. This is important because if an error occurs while the HMI is operating, the equipment also shuts down, resulting in costly downtime and lost productivity.
How can we interpret this information to prevent this from happening? From our HMI experience at T2 Industrial, these are the 5 most common HMI faults to watch out for.
1. DIFFICULTY POWERING-UP
If your HMI tries to turn on repeatedly or requires frequent power cycling (resets), this is a typical sign of premature failure. An HMI initialization problem indicates an imminent failure of the internal power supply.
2. UNRESPONSIVE KEYPAD
Keys that are commonly used in HMIs are prone to failure at first. Keys such as the Start, Enter, or password keys may be used frequently and identification symbols may be worn out. Operators may find that they press a key a little harder each time, and eventually, these keys fail. This indicates a faulty switch and you will need a new switch or even a whole new membrane.
3. LESS RESPONSIVE TOUCHSCREEN
Some common parts of the touch screen may fail or force the operator to press a soft button repeatedly to get a response. This is a sure sign of a malfunction of the touchscreen element. Touch screens are very sensitive and wear out like any other part. You must use nothing but your fingers to work with them, otherwise, they may itch and break. Breaking the LCD glass can cause the HMI to fail immediately, and moving the screen with a pen or other tool increases this risk.
4. DULL OR FLICKERING SCREEN
This can be annoying for the operator, but it is more important because it indicates an immediate HMI backlight failure. The backlight can take several months to completely fail, so you have plenty of time to install a replacement unit or upgrade the HMI.
5. LINES ON THE SCREEN
Vertical or horizontal lines on the screen are equally annoying, but they indicate an early malfunction of the LCD screen. Like the flickering, it starts appearing on a few lines and takes some time to stop completely, but that is a sure sign of failure.
Preventative Maintenance
Many of these symptoms appear months before a complete failure occurs, so an ongoing conversation with system operators must be initiated to prevent this from happening. They are the ones who interact with the HMI every day and tolerate small problems instead of fixing them. If operators learn to recognize these 5 early indicators of common HMI failures, they can more easily manage their system without sudden and unexpected failures.
Here’s some predictive maintenance that takes the form of simple questions.
- Does the HMI start immediately every time?
- Do your touch screens or membrane keys react less?
- Have you noticed that the screen flickers or looks dull?
- Do you see any lines on the screen?
The operator’s answers to these questions should inform you about likely HMI failures and the need for refurbishment or replacement. Don’t wait for an operator to tell you after a break that some of these symptoms have been occurring for months. They don’t go away on their own and preventative maintenance helps avoid downtime and loss of production.
By following these simple predictive maintenance questions, you can prepare ahead of time what replacement parts to look for. If you need guidance or any help on how or what to replace your HMI, our team of experts is available just give us a call or send us an email.
We have multiple replacement parts for units like Allen-Bradley, Siemens, Anilam, Dynapro, Fanuc, and a lot more. You can check our product catalog here.
