Wireless is getting more invisible, but it's also more helpful than ever.
It's not logical that the more accepted a technology gets, the more it's taken for granted and becomes transparent—quite a trick for wireless that's already mostly unseen. However, in a world of alarms, runs to failure and squeaky wheels, it's apparently inevitable that quiet competence fades into the background and gets ignored. Just ask all the utilities and water/wastewater operators, most process engineers and every other support industry and profession. They're all invisible until something breaks, someone doesn't immediately get what they want—or a new crisis emerges.
In any event, just as it can save on cabling, and bring in signals and data that would be inaccessible or too costly to acquire, wireless can also connect users and applications separated by the COVID-19 pandemic, just as it enables and is aided by operations technology (OT) and information technology (IT) professionals coordinating their tasks.
"Wireless is growing fast, especially due to COVID-19, which is bringing more users seek remote connections," says Penny Chen, senior principal technology strategist at Yokogawa's U.S. Technology Center. "However, even though it's more ubiquitous, wireless still requires users to determine the right type, such as Wi-Fi, ZigBee, Bluetooth, ISA100 or WirelessHART, which will work best in their specific applications and environments. The big hope now is that 3GPP, V.16, non-proprietary cellular, or 5G, will also support lower-power IIoT devices or real-time task execution, including controlling robots and other devices. It's already being tested and applied in Europe, along with low-power, wide-area networking (LPWAN) and the long-range WAN (LoRaWAN) protocol."
This is Part 1 of a three-part series on wireless. Read Part 2.
Site survey still essential
Even though it's made many advances and is simpler to use, wireless is still subject to the unique differences of individual applications and environments, which means site assessments are still required to pick the right method from its expanding bag of tricks and apply it for more effective and reliable performance.
"We still have to ask what power, distance, and data amounts and speed each wireless application and its sensors need, and whether Wireless HART, ISA100, LoRaWAN or whatever is the right choice," adds Chen. "There's also the effect local geography or plant with a lot of structural metal can have on network topology. Because of this, every wireless manufacturer has a wireless survey guide, which indicates where to put wireless access points and address other issues. However, it's still up to each customer to decide on what wireless approach will be right for them based on what their operations and applications need today and tomorrow."
For instance, Toray Fine Chemicals Co. (TFC) in Chiba, Japan, is reported to be its nation's only producer of dimethyl sulfoxide (DMSO) and polysulfide polymer, and its plant uses four partly buried, concrete pits to biologically treat wastewater from its production process before it's discharged to the public system. Intermediate treatment liquid stays in the pits, which are legally required to be periodically monitored for structural soundness and possible leaks that could contaminate local groundwater and soil. Because it's difficult to examine the bottoms of the pits or empty them to check for cracks or other damage, TFC usually performs an annual, two-day, water-logging inspection process, which fills the four pits with water, and uses a level gauge and recorder to check for any level decreases. This process requires TFC to halt parts of its water treatment and delay production, so the inspections must be completed as quickly as possible.
To speed up its inspections, TFC installed a Rosemount 3308 wireless guided wave radar (GWR) transmitter from Emerson on each tank, which improved inspection accuracy and repeatability from 5 mm to 2 mm. It also employed WirelessHART protocol that's unaffected by obstacles, used a digital signal instead of analog 4-20 mA to reach its DCS, and eliminated connection wiring for easy relocating (Figure 1). TFC reports it reduced pit inspection time by 75%, even though Rosemount 3308 cost less than half as much as its original analog instrument system, saving a total of $9,000. It adds the new inspection solution also reduced required labor from 22 hours to just 5.5 hours, and minimized wastewater treatment downtime, saving an additional $27,000 per year.
Choose, collaborate and control
"Wireless has become just another networking choice. When we talk about it, we talk about the solutions wireless can enable, not if it's possible to use it," says Shane Hale, global business development director for Pervasive Sensing wireless products at Emerson. "These days, it can take as little as 10 minutes to add the sensors for wirelessly monitoring steam traps, pumps, pressure reducing valves (PRV) or heat-recovery steam generators. Because it takes so little time, we can add an acoustic and temperature sensor to an application, listen for the whistle, and experiment with what works best. Wireless enables more experimentation in process measurement and analytics. For example, in edge-based machine learning (ML), there's a big move to cloud computing and getting data to it, and wireless can help deliver it."
Similarly, because COVID-19 has limited staffing on many plant floors and in many industries, Hale reports wireless can benefit the remaining operators and technicians, who have less time to walk around and perform manual checks, and could use an assist from automated, wireless rounds on pressure readings, level gauges, switches and other components. "A year ago, few companies were spending extra on automating manual rounds, and during the last six months, everyone was too busy to think about it, but now they can justify it," says Hale.
To get more data in front of everyone in their plants, Hale reports some users are combining Wi-Fi and WirelessHART infrastructure, so they can more easily view production data, live documents and instructions at the same time. "WirelessHART is joining Wi-Fi as a regular part of some IT networks in plants, just like the wireless you'd expect to find in an office," explains Hale. "This means users who want to add wireless sensors to a pump no longer need to also think about installing a gateway. Now, because the network is already there as part of the wireless infrastructure, all they have to think about is installing their device and switching it on.
"However, this is where IT and OT cooperation becomes more important. We worked with a chemical plant on the Gulf of Mexico that had WirelessHART, but when their IT department put in Wi-Fi without considering the existing wireless installations, there were many data collisions, some WirelessHART devices went offline, and there was a lot of finger pointing. IT had to talk to the plant staff because, while IT knows its network, data flows and office infrastructure, it usually doesn't know the plant's operations and priorities."
Conversely, Hale adds that OT and IT collaboration is also needed to prevent both from doing too much, working in the wrong place, or otherwise misapplying their labor. "IT and OT can work together well, but they still need to evaluate their organization's unique use case," adds Hale. "Just a couple of weeks ago, we worked with a Canadian chemical plant and its staff, who wanted to cover its entire site with every available communication protocol, even though in the tank farm there was no need (or products available) for one of the protocols they were designing for. The additional infrastructure to cover the tank farm for this third protocol added cost for zero benefit."
Hale explains the use case defines and justifies investing in wireless, such as settling on what protocol is needed and where, is it for monitoring or control, and how often will these functions need to be performed?
"It's true that wireless is OK for controlling some slower-moving applications, but the question is how to make sure they're safe? This is a new frontier," says Hale. "Users want to get experience and build trust by first using wireless for measurement and monitoring, and then they can begin to use it for non-critical control. For example, this could be done in the liquid level control in a separator, which doesn't change very fast, but usually needs an operator to walk up and check every two or three hours. In this case, wireless control could be added to the level switch or the guided-wave radar level transmitter and to the on/off valve. Wireless valve positioners can also be bolted onto actuators, so operators don't need to walk around and check them. Because WirelessHART uses a self-organizing wireless mesh that doesn't need line-of-sight to reach its gateway, devices will use other wireless devices to get home if there's an obstruction. This makes it more resilient, and enables it to achieve 99.9% uptime, which is well within the requirements of non-critical control loops."
Though most users still prefer to employ wireless for process monitoring and data gathering, Yokogawa's Chen reports more are also starting to use it for control. "We helped build ISA100 for wireless sensors, and demonstrated it can be used for closed-loop control," says Chen. "However, wireless can also provide backup that's cost-effective. There have been times when wires broke in fires, but wireless was still available. There are many other creative applications for wireless, such as floating with oceangoing devices to make up for subsea cables.
"We recently worked with a lubrication manufacturer that ships its products in railcars that sit on sidings for a long time in winter and summer, which affected the stability of its lubricants. The company wanted monitoring that didn't require people, so we did a site survey, and implemented ISA100 wireless sensors. They perform continuous, real-time temperature monitoring, provide alerts if the product is overheating, and can even stop the loading system if necessary."
