How to buy the right Human Machine Interface (HMI) hardware
If you're in the market for an HMI, there are about 250 different brands currently listed on Google so you're not short of options.
However, you’ll quickly find those options diminishing as you count off your specific needs. So what's the right HMI for you? Here are a few tips to narrow it down.
Know your HMI options
Basically you can break HMIs down into three categories: pushbutton replacer, data handler and overseer. The pushbutton replacer is, as the name suggests, an HMI that replaces buttons you push with touch screens or keypads. The data handler is also true to its name; an HMI adept at storing and displaying manufacturing data, anything from trending and logging to recipes. Last but not least, the overseer effectively watches over and troubleshoots the manufacturing process.
Know your environment
What's the operating environment of your HMI like? Is there electrical noise, vibration, excessive water from wash down, extreme temperature near blast furnaces, or bright sunshine to contend with? Each scenario cuts down your HMI options and calls for extra consideration of hardened industrial panels, ingress protection and screens that are easy to read outdoors in bright daylight. If you're worried about how your HMI will hold up in your conditions, err on the more heavy duty side to save costly replacements later.
Know what you're using the HMI for
And that means everything it's going to be used for. Plan ahead and nut out all the possible additional requirements that could come up. Leave room for expansion of memory and function keys to be on the safe side.
Know what it's connecting to
Try to ensure that all components in the system are from the same company. If something goes wrong it’s far easier to deal with the issue via one vendor than have several companies trying to steer responsibility and/or blame to the other.
Know your operator's data entry preference
Basically it's touch screen or keypad, so not a hard decision. It just comes down to what your operators are more familiar and comfortable with. Make sure you involve them in the purchase process to ensure they get what works best for them.
Know your technical backup
Can you talk to a real person or just an online robot? What does support cost if anything? How fast and efficient is their onsite support? These will be defining factors in your ultimate choice of HMI brand.