Mobile HMIs have been discussed everywhere for many years now, including hard hat-mounted proprietary systems more than a decade ago. However, despite all the marketing about HMI “anywhere, anytime,” we still don’t seem to have much penetration beyond the more traditional wired panel. The incongruency is that most of us have a smart phone, and use it all the time for much more than simply a phone or camera—my wife certainly reminds me that I spend too much time looking at that thing.
Other than our industry’s traditional reluctance to adopt new technologies, what are some of the reasons and challenges faced by the mobile HMI? In no particular order, the following quickly come to mind: cybersecurity, integration, intrinsic safety, coverage and risk management. Let’s look at each of these a bit further.
Cybersecurity is certainly a consideration for any connected device, and especially for one connected to a control system, since many mobile devices such as tablets and phones don’t have the same level of hardware and software protection as a dedicated hardwired system. Wireless cybersecurity is improving by leaps and bounds with access points, white and black lists, etc., but unless mobile device use is restricted (i.e., control system only), it will likely be used to access secure and unsecure information on the same hardware, increasing the possibility of being compromised.
Integration is necessary on multiple levels. If the intent is to allow use of “any” device, system administrators could need to support, for example, Android, Linux and Windows systems on equipment from Apple, Google, Samsung, Nokia, Huawei, etc., as well as industrial devices designed for the plant environment (dust, moisture, etc.). There are ruggedized computers, tablets and phones on the market today, including intrinsically safe units, suitable for use anywhere, so the plant environment issue can be addressed for a cost, and with devices not likely to be available in the normal consumer marketplace.
Another integration challenge is the interface itself. Fortunately, the majority of HMI products are moving to a web-based presentation, and international standards support consistency across almost any platform from a multi-panel wall screen to smart phone. This challenge appears to be well in hand.
I've mentioned the coverage issue many times in the past—the need to put in infrastructure can limit introduction of wireless devices. A corollary challenge, once the license-free infrastructure is in place, is that almost all of it relies on using the 2.4 GHz spectrum, so now you also need a plan to manage available channels to ensure your priority messages get through before other traffic. For example, HMI update, WSN signal, maintenance vibration measurement, and accessing maintenance manuals, walkdown checklists, etc., are all use cases for the roaming HMI and wireless infrastructure. I believe that in the next five years, this will become less of an issue as different 5G networks, enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), and ultra-reliable, low-latency communications (URLLC) implementations become available.
This leaves the largest challenge—risk management. Most facilities will want to be sure that the system has incorporated enough safeguards to allow unattended remote operation. SCADA systems are a good example of this, with occupancy detection plus cameras to ensure that if someone is present, communications are in place to prevent injury from remote operation of equipment, or that the person making the change is close enough to the process to be aware of local hazards. Use profiles will become increasingly important, and may incorporate location awareness as part of that profile to prevent someone from accidentally operating a plant from home on their mobile device.
For these reasons, mobile HMI is another of the automation sector’s examples of marketing versus implementation. Even so, I'm confident the use of mobile HMIs will continue to grow, though the rate of that growth is likely less than market studies might suggest.
