Unlike some of the other parts we come across, HMIs (Human Machine Interfaces) usually display tell-tale signs that they need some TLC before failing completely. This gives companies the opportunity to decommission and service the unit at a time that is least disruptive to production. So what are the tell-tale signs that your HMI or operator panel needs a repair or service? Pay attention to the warning signs below and act on them to minimise the chance of unexpected downtime.

What signs should you look out for?

You turn the brightness all the way up but the screen is still dim

This is a sign that the backlight needs replacing. Swapping the backlight before it goes completely means you can take it offline when it is most convenient, rather than when the backlight fails totally and it’s no longer possible to view what’s on screen.

The monitor display takes longer and longer to turn on

This is typically a sign that the HMI is getting old and so are the components inside. Changing the components, such as capacitors, will breathe new life into an operator panel and enable you to get additional time out of it. This also costs less than replacing the whole unit when suffering downtime when the HMI fails to turn on at all.

The display has a chip or is beginning to crack

A chip or crack in the display is only going to get bigger and will eventually render the HMI unusable. Replacing the display glass is a lot simpler than fixing additional damage caused by something going through the display where it has weakened.

The touchscreen is unresponsive in sections

An unresponsive touchscreen can be down to a few different things, from as simple as it being too dirty or greasy depending on the environment, to the software needing recalibration. Sometimes, on older screens, the glass may have had too many small scratches due to constant use and requires a replacement touchscreen. 

Half the LCD screen is dim

When the screen begins to dim, the HMI is giving you warning signs that the backlights are about to fail. You may get a few months longer out of the screen before the backlight completely fails, so it’s worth swapping for a replacement or repairing the HMI when it is most convenient.

There are lines across the screen

If you can see lines on the HMI’s screen, whether horizontally or vertically, it means that the LCD is failing. Like other HMI issues, it will be possible to continue use of the screen for a while whilst the lines are few and far between, but eventually the LCD will fail altogether.

Prevention is better than cure

Ignoring problems like the above can cause irreversible damage to your HMIs. This is because parts like electrolytic capacitors can dry out or leak onto the internal circuit board which has catastrophic results.

Many of the problems above can be eliminated by carrying out preventive maintenance on the equipment at scheduled intervals. Preventive maintenance is a schedule of planned maintenance actions aimed at the prevention of breakdowns and failures. An industrial operator panel properly specified can last a good seven years before failing, but a simple service can ensure trouble-free operation for twice as long as this. In the long run preventive maintenance helps reduce maintenance spend and avoids the stress caused by downtime.