New HMI alternatives improve operations and cut costs
Today's businesses demand easy and inexpensive HMI remote access along with the ability to quickly retrieve and act upon plant operating data
- Users must first decide whether their HMI should be PC-based or embedded.
- Once this decision is made, they can determine the best methods of remote access.
- Technologies borrowed from smartphones and tablets are rapidly improving remote access.
By Jeff Payne
Faster speeds, lower costs, and greater connectivity are essential to the success of all businesses, including manufacturing. With the introduction of lean manufacturing, Six Sigma, and other continuous improvement strategies, operations must become more flexible, easier to manage, and less expensive.
To achieve these goals, businesses demand user-friendly human-machine interface (HMI) graphics, the ability to drill down quickly for alarms, overall equipment effectiveness dashboards, and more. In addition to having reliable information at their employees' fingertips, companies also want better remote HMI access from a variety of devices. Finally, they want more intuitive interfaces to reduce training costs and improve operator performance.
Fortunately, there are HMI packages available that can fulfill all these requirements. The latest HMI software solutions shorten development time, offer better remote access, and have more intuitive interfaces to reduce the learning curve for operators and other users. Overall, these enhancements facilitate a more mobile and productive workforce while reducing training and equipment costs.
Is a PC the best choice?
When selecting an HMI, the first decision is whether or not it will be based in a PC. PC-based HMIs have the best performance, the most features, and the easiest connectivity-but also have the most expensive software licensing costs. HMIs that are not PC-based typically run on embedded operating systems. These embedded HMIs are much less expensive than PC-based HMIs in terms of software licensing costs, but are also less capable in performance and feature richness.
With respect to hardware, costs depend on whether the HMI will be in the controlled environment of a control room or an office, or on the plant floor. In a controlled environment, a PC is less expensive than a similarly sized embedded HMI. But on the plant floor, an embedded HMI is much less expensive than an industrial PC. For many applications, connectivity and remote access will drive the PC versus embedded decision.
Mobility is no longer just an option
No one can now imagine a successful company that does not have remote access to business systems; the same will soon be true for automation. With just five operators being hired for every 10 that retire, mobility is essential for increasing productivity. Employees can no longer spend the entire day in the control room or one area of the plant, thus HMI remote-access capabilities are mission critical.
Mobility is often provided through wireless and cellular networks. Although security is a concern, wireless networks are rapidly becoming an accepted medium of communication in industrial environments. Lower installation and maintenance costs along with improved security have made wireless attractive to automation companies. Wi-Fi and Bluetooth are affordable, fast, and easy to use. And thanks to the evolution of encryption and the IEEE.802.11X-based Extensible Authentication Protocol, user devices must be identified to gain access to the network. Cellular networks are an attractive alternative to wireless in many cases, particularly as speeds are increasing while costs decline.
What kind of remote access is best?
When developing remote-access applications, the type of user and his or her requirements must be considered, along with costs. Evaluating these and other factors will determine the appropriate method of access from the listed options.
Note that most companies will use multiple methods of remote access, mixing and matching depending on the specific needs of the particular user, on the costs involved, and on the technical capabilities of the organization.
Most every PC-based HMI will support all four remote-access options, whereas most embedded HMIs will only support web browser and app access. Embedded HMIs are meant to stand alone for the most part, whereas PC-based HMIs are often part of a networked system of PCs and thin clients.
Remote access via a PC has the best remote user experience. PC remote access is very low in hardware cost if the user already has a PC and is using it for other purposes. But networking a remote PC can be expensive, and software licensing costs are high. If the remote-access PC needs to be mounted on the plant floor, costs will be very high.
A better alternative for plant floor remote access is a thin client, which has nearly all the capabilities of a PC at a much lower cost, both in terms of software licensing and especially hardware. Not only is a thin client less expensive to purchase, it is also much less expensive to mount on the plant floor. It will have much less processing power than a PC, and hence generate less heat. Thin clients are also much less expensive to maintain than PCs, as most all software is installed and maintained at the PC-based server as opposed to on the thin client.
Whether the HMI is PC-based or embedded, browser and app access are two other remote-access options that should be considered and evaluated.
Browser or app?
In today's plants, operators must monitor and control more processes in multiple places. They must be able to quickly and easily access HMI information from mobile devices from any area in the plant or outside it.
Moreover, the growing trend of "bring your own device" (BYOD) means companies can save money on hardware and software. However, BYOD also means authorized users will be accessing HMI data from a wide array of devices such as iPhones, Androids, iPads, tablets, and PCs.
In response to their customers' needs, HMI suppliers have designed products for remote interaction via a web browser or an app. Both options have advantages and disadvantages, depending on how they are accessed.
Browser access typically works seamlessly for PC users, but the web server screens do not often scale well to the smaller displays on handheld devices. The screens can take too long to load, and only a small portion of the display may be visible. Browser-based access is often free in terms of software licensing costs, but the expense of designing, deploying, and maintaining the network and web servers can be substantial.
Apps are usually the faster, easier choice for handheld device users. Free or very low-cost apps are created for smaller screens to improve download times, and software licensing costs for host software are usually either zero or very low. Apps provide users with better visualization and much faster interaction, two key attributes for remote access (figure 1).
Figure 1. Apps have accurate displays of the HMI graphics, along with very fast interaction.
The downside to using apps, however, is they are usually first developed for iPhones and iPads, with apps for other devices, such as the Android operating system (OS), lagging. This is because a large number of vendors sell tablets and smartphones, and there is consequently a lack of standardization.
Android-based devices alone come in at least seven screen sizes. The lack of standardization has made it cost prohibitive for HMI suppliers to develop an app for every handheld device's screen size and OS. Moreover, users do not want to wait months or years for the app to be developed for their particular device. Fortunately, there is a solution, and it involves the adoption of the HTML5 standard.
Software standards to the rescue
For thousands of users, it seems as if the ability to use an Android or tablet for HMI access is merely a dream. However, the releases of Windows 7 and 8, which both have HTML5 support, promise users fast remote connectivity, regardless of their device type. HMI software packages with HTML5 support enable users to get simultaneous remote access from almost any device, without waiting for an app to be created for their specific device. The "design once and deploy everywhere" approach allows delivery of remote-access capability by the software supplier to any device with HTML5 support, regardless of the OS or screen size (figure 2).
Figure 2. HTML5 support offers HMI app access from a wide variety of portable devices, without the need for costly and time-consuming custom software development.
App access was initially a feature restricted to Apple platforms, and that is still the case for some HMI software suppliers. But the demand for apps that work with smartphones and tablets from other vendors is so great that HMI suppliers will start to develop apps that use HTML5.
Multitouch improves performance
It is easy to see how reliable and fast remote access benefits businesses, but multitouch capabilities may seem like more of a gimmick to entice younger workers. While it is true that tomorrow's employees will likely have rarely touched a mouse or other pointing device, multitouch enables all workers to improve performance.
Multitouch HMI offers many advantages over single-touch screens, keyboards, and pointing devices. It recognizes the position of several touches and finger movements, which are referred to as "gestures." Training time is shorter, because these gestures-pinch, zoom, swipe, and more-are the same as those used for smartphones and tablets.
By using gestures, operators can execute commands up to three times faster than those performed on regular touch screens. The ability to easily manipulate objects on the screen also helps them find the exact location of a potential problem quickly. For example, an operator might get an alarm about a certain piece of equipment. Using multitouch technology, he or she can easily rotate a piece of equipment on the screen, zoom into a specific area, and then magnify the area-all without once lifting a finger from the screen. When an event occurs, an operator can quickly zero in on areas of interest, instead of wasting time using drop-down menus or scrolling through multiple screens.
The fewer moving parts of multitouch tablets make them a better choice for workers who visit dusty, wet, and corrosive environments. Industrial tablets have the durability required for these areas, and many can be operated while wearing gloves. Furthermore, they can improve worker safety through the creation of commands that cannot be performed unless both hands are on the screen.
Although it is unlikely that businesses are going to swap their functioning screens for new multitouch ones, it is highly probable they will replace worn-out screens with multitouch capability as the price for these devices drops. Multitouch functionality is also expected to become more ubiquitous due to the integrated support for the technology in new Windows operating systems. Eventually, all screens will likely have multitouch capability, so it is smart to select an HMI package that supports it.
While the automation world can be slow to implement change, it is being forced to increase performance and decrease costs and will need the technologies that can help accomplish these goals. Forward-thinking HMI vendors are ready for these challenges. These suppliers see BYOD as being the norm rather than the exception. They are offering solutions with HTML5 support, so companies can quickly and easily connect remotely to a wider array of portable devices. They comprehend that multitouch is new to automation companies, but they realize the sea change that is coming when these enterprises discover how much they can improve operations.
More than ever before, seemingly future technologies and applications are rapidly becoming the staples of today's businesses, and the companies that implement these advancements will stay ahead of the competition.
ABOUT THE AUTHOR
Jeff Payne (firstname.lastname@example.org) has worked in industrial automation for more than 25 years; he is the product manager of automation controllers and interface software at AutomationDirect.