Human machine interfaces (HMI) have become a staple component of modern-day businesses. As the name suggests, they provide an “interface” through which human operators can control machines. HMIs are being used in automobiles, hospitals, retail stores, restaurants, and production factories. When designing an HMI for outdoor use, however, there are a few things to consider.
If the HMI is equipped with an electronic display — touchscreen or standard — you should be aware of the potential for glare. As the sun beams down onto the display, it can make reading and using it difficult. Thankfully, there are several viable solutions to this problem, one of which is to choose an HMI with anti-glare finish, such as a matte finish. The application of these finishes helps to mitigate the distracting glare caused by both sunlight and artificial light. Alternatively, you can install a separate screen “shield” over your HMI’s display, protecting it from sun glare.
Something else to consider when designing an HMI for outdoor use is whether or not to make the system waterproof. It’s a common assumption that waterproof HMIs are only necessary when used in uncovered areas that are directly exposed to the elements, but this isn’t necessarily true. Even if your HMI is placed underneath a roof or some other covered facility, the outdoor humidity could damage its internal electrical components. By making it waterproof, however, you’ll prevent problems such as this from occurring.
Membrane Keypad or Non-Membrane
Do you want a standard keypad or membrane keypad to use in conjunction with your HMI? Standard keypads are more prone to damage, as the keys are separate parts that are not attached to the bottom. Dust, dirt and debris may become embedded underneath the keys, preventing the HMI from properly registering those keypresses. Thankfully, this isn’t an issue with membrane keypads, as the keys are integrated directly into the pad, meaning there’s no space or area underneath them for dirt and debris to linger.
These are just a few things to consider when designing an HMI for outdoor use. Consider your needs and the way in which the HMI will be used. Because every company has different needs in regards to application, there’s no single “best” type of HMI.