Today we live in a world where touchscreens are ubiquitous. We see them in use in phones and tablets, laptops and desktop computers, and even TVs. The rise of the touchscreen has driven rapid change across all industries. But what is essential to look for when buying Human Machine Interface (HMI) touch screens? Let’s look now!
What HMI Touch Screens Are
When it comes to plant operators and those in similar roles, the utilisation of Human Machine Interface (HMI) touch screens offer a number of benefits over the traditional mode of using physical switches, lights, and buttons. Once in years gone by it was necessary to rely on these analogue options – and trust in the fact the additional parts like lightbulbs in the lights and springs in the buttons weren’t faulty! – to perform operations and routine checks.
Today HMI touch screens offer a precision and reliability that is a great improvement on the old analogue setup. But if there’s one extra challenge that comes with using the new over the old, it’s that HMI touch screens have a greater array of variety in what they can do, and accordingly selecting one requires a consideration of some particular features and how they may fit an operation’s needs.
Understanding the Three Basic Types of HMI
At a basic level, each HMI performs a similar
task. Helping an operator to run a plant or process.
Yet beyond the foundation shared in common, there are HMIs that specialise in
particular areas. First, there’s the overseer HMI. Whenever you have an
overseer HMI in use alongside Supervisory Control and Data Acquisition (SCADA)
or Manufacturing Execution Systems (MES) the benefits can be immense – but an
overseer HMI shall also likely require it be run in tandem to Microsoft Windows
(more on that shortly). Second, there’s the pushbutton replacer HMI. This HMI
has a streamlined and centralised design that sees all functions and all
buttons in one location.
Third, there’s the data handler HMI. This HMI can be ideal for operations and processes that require constant and ongoing feedback, including printouts of data.
An All-in-One or Separate Setup?
With modern HMI touch screens it’s possible to have an all-in-one setup. A system where all the needs and functions of the HMI can operate totally contained within the HMI unit itself. But it’s also possible (and potentially necessary depending on an operation’s own particular needs and wants) to run the HMI with a PC too. This can increase functionality and the range of capabilities but – especially if operating in an area of the factory floor or similar where space is a key consideration – it may not be necessary, and some ‘workarounds’ can be found if desired to run on a HMI-only setup.
Screen Size
Just as the size of a smartphone or TV can inform the enjoyment of using it, the same applies to a HMI screen. It’s important to remember even if someone is fortunate to be able to work effectively with a small screen size, other staff who may use it could find it a challenge. If someone is running a HMI with a PC hookup this may not be as critical a consideration.
But even so, there could be times where it’s necessary to rely on the HMI machine and its display exclusively. It’s also essential to consider the resolution of screens. The higher the pixel density, the smoother the screen’s display will appear. This accordingly is easier on the eyes as it reduces eye strain, and makes it easier to read text and other data. If a HMI touch screen is used sparingly then resolution may not be a dealbreaker, but it certainly could be if there’s an intention to use it regularly.
As a rule, when there’s doubt, seeking out a HMI with a large screen is usually ideal to ensure all can utilise it with ease and comfort. The same applies to resolution. The higher the better, especially if it’s anticipated the HMI will be used by staff members who have challenges with their vision and eye strain.
Which Software to Utilise?
As well as looking to Microsoft Windows utilising an overseer HMI, there’s also programming software to consider when buying a HMI. There’s a choice shall be between open software, hardware independent software, or proprietary software. Each has their own pros and cons, but it is ideal to consider the software when going through the HMI buying process, so as to ensure the capabilities of the machine and the program used with it is maximised.
Pushing the Right Buttons
Ultimately the foremost consideration when buying a HMI touch screen will be the particular needs a plant or process. Every circumstance is different, but there are common considerations that all buyers of a new HMI need to consider. Possessing an understanding of the different types of HMIs, their screen size and resolution differences, and which software may suit a HMI and a businesses’ particular needs is key. There’s now all that’s needed in-hand to begin the browsing process!