HMI checklist: What to consider when shopping for an HMI solution

Jul. 14, 2016 – In today’s manufacturing landscape, many companies are challenged to do more with less, while meeting the growing demands of their customers and facing increased global competition. It’s this need for greater productivity and efficiencies that is fuelling the demand for industrial automation, and with that, the demand for human machine interface (HMI) solutions — a combination of hardware and software that allows users to connect, monitor and control increasingly complex industrial automation equipment, and visualize the data coming from these machines.

HMI solutions have evolved in recent years, and offer more capabilities than ever before. They’re no longer just push-button replacers. Today’s HMIs can be so much more — a troubleshooting tool, a data logger, a device to remotely control and access the machine, and a communications interface between multiple devices.

As more options and features become available, the selection process becomes increasingly challenging. And whether the customer is an original equipment manufacturer designing and selling machinery, or an end-user working with the machine, there are certain factors to consider to help determine the appropriate solution that will best meet your needs, or the needs of your customers, now and in the future.

With that in mind, Manufacturing AUTOMATION asked HMI experts from Idec Corporation, Unitronics, B&R Industrial Automation and Red Lion Controls about the major factors to consider when selecting an HMI solution, and which features are most important for manufacturers today. Based on their input, we developed this checklist.

Key considerations
The environment: Consider the environment that the HMI will be operating in — whether it’s outside in below freezing temperatures, in a refrigerated environment indoors, or situated next to a boiler. Depending on the environment, rugged packaging that can withstand vibration, extreme temperatures and more may be essential. Most HMI providers have a wide selection of both indoor- and outdoor-rated devices available with broad temperature ranges.

Communication needs: An HMI panel is essentially a communication centre that acts as a gateway to your control system. As such, it must provide connectivity and support a range of protocols to bridge the communication between the control application and enterprise resource planning (ERP), explains Benny Magrafta, R&D manager, PLC + HMI development (Software) with Unitronics.

Paul Bunnell, director of automation products with Red Lion Controls, says it’s important to consider which communication networks the HMI needs to talk to. Some manufacturers may have “disparate-type products” on their plant floor that mix old and new technology. He says users may want to consider an HMI solution that can talk several protocols or that offers protocol conversion for added versatility.

Screen size: Depending on the complexity of the machine or process that is being controlled, screen size can be a big factor, says Bunnell. These days, HMIs are offered with a variety of screen sizes. A larger size can show more information and more complex data, but it comes at a higher price point. Non-complex applications may only need a small screen.

HMI provider and support: When it comes to selecting an HMI provider, Magrafta recommends choosing one “with a proven track record — one who can provide you with tried-and-true technology, while staying current with worthwhile technological trends.”

And, says Bunnell, make sure the HMI manufacturer supports its older products. “If I’m upgrading to a newer technology, is it a form function fit? Will the same software be able to be reused or converted? Things like that are very important,” he explains.

Derrick Stacey, a solutions engineer with B&R Industrial Automation, recommends selecting a provider with products that are “backwards compatible.”

“Make sure things are very backwards compatible, so that when they come out eventually with HTML6, 7, 8, anything done in HTML5 will still be supported,” he says. “The more open it is, the more established architecture that you use, then you won’t have to worry about a ‘phasing out’ situation.”

Britt Davis, automation and safety sales manager with Idec Corporation, says end-users should ask HMI providers what kind of support they offer. Ask if free technical support is available, as well as free local support — not just via an 800 number or a website.

Must-have features
Web server capability and remote access: An HMI with a built-in web server is a must, says Bunnell, because it gives users a remote view of what the HMI is looking at. “I can be anywhere in the world and remotely connect and then see what’s going on in an application,” he says.

Remote access allows users to monitor and troubleshoot wherever they are. And it’s a cru- cial capability in today’s mobile world — one that will help minimize, and ideally avoid, sys- tem downtime. It also allows users to remotely modify or update the HMI application.

Web-based tools also offer more design options.

With the right software, you can design web pages without knowing any HTML or Java, and access them via any Internet browser. Many of today’s HMI panels support HTML5 and .css, and this is a must, Magrafta says.

Data management: For many companies, Bunnell says, it’s important to have the capability to capture data, as well as date and time stamp it for archive purposes, so that they can go back and look at what went on at a particular point in time.

HMIs should have data management tools that enable runtime data to be logged, manipulated and sent as reports via email and ftp, says Magrafta.

Display backlight: Davis says to pay close attention to the type of display backlight being used, as well as the backlight life rating and the brightness of the overall display. “An HMI that uses an LED backlight with a high backlight life rating and a bright display will look better, for a longer period of time, than one that doesn’t,” he notes.

Multimedia support: There is a trend to include video and audio in HMI applications. This feature is very effective in guiding machine operators through troubleshooting, setup and more, says Magrafta. PDF support is also key, as it enables an operator to access complete operating manuals and read them on the HMI screen, he adds.

User access control: Not all users are meant to have access to every detail on an HMI about a machine or process. User access control, and features like multiple password protection, offer the ability to protect the application from unauthorized entry.

Alarms: An HMI with the ability to notify managers of developing situations — via alarms, emails or text messages before they turn critical — is a huge benefit because it can help operators avoid downtime by informing them of potential problems and provide them with instructions on how to prevent issues, says Magrafta. Embedded diagnostic apps are also important because they can easily run updates, diagnose issues and capture data, he adds.

Ease of use: A well-designed HMI solution makes it easier for the user to interact with the machine. And, since many advancements in HMI technology have been driven by consumer products, more and more solutions are beginning to behave like consumer devices.

“What we’ve seen in talking with customers is the faster they can get an operator to understand and get comfortable with the screens of their HMI, then it requires less training, there’s less user fatigue,” says Stacey.

Ease of use extends to application programming. Easy, fast HMI application programming is at the top of the list for Magrafta.

Expandability: Bunnell thinks that every HMI should have multiple connections to it, such as Ethernet and serial ports. He encourages end-users to consider the future when selecting an HMI and look for something that offers expandability.

Making a list, checking it twice
Indeed, there are many factors and features to consider when selecting an HMI solution, but the most important point to remember during the process is what the end goal is — maximum productivity.

“It’s critical to have machinery operating at maximum efficiency,” explains Bunnell. “And getting information out of that is the best way for companies to manage their assets.”

HMI solutions — and their increasingly impressive capabilities — are a critical tool to help manufacturers achieve their productivity goals.

Mary Del Ciancio is a Stouffville, Ont.-based business writer, and a former editor of Manufacturing AUTOMATION.

This article was originally published in the May 2016 issue of Manufacturing AUTOMATION.