Getting all the information out of that more powerful PC or PAC to where it needs to be in as near real time as possible is the premise behind bringing handheld communications devices to the factory floor and more remote locations.
What people find so attractive is the real-time component, says John Lindsey, executive vice president at Rapid Solutions USA, a subsidiary of systems integrator Rapid Technologies in Calgary, Alberta, Canada. Real-time capability puts all the information in the hands of the workers, and gives them decision-making capabilities. The goal is to enable them to work in real time on non-DCS equipment. It saves time, and more important, it stops them from making poor decisions in the field.
That said, a handheld device isnt meant to be a substitute for desktop computers or control room SCADA/HMI systems, says Michael Saucier, founder and CEO of Transpara. Handheld devices augment the desktop and give users access to key decision-support systems in a way they havent had it before. They provide a new use case for existing information. Its not a new system, but its taking what you already have and using it more efficiently.
Cutting the Cord
The main driver and basic supporting technology for pushing handheld devices onto the factory floor and out into the field is wireless. Once the cord between the computer and reporting devices literally is cut, any device, from a ruggedized laptop to a tablet PC to a smart cell phone, becomes a candidate for a suitable information-delivery device, and more than ever, successful process manufacturing is all about access to information, not just in the control room, but everywhere and anywhere.
Theres been an enormous amount of downsizing. Each person is taking on more roles and responsibility, says Saucier. People are at their desks much less than they used to be. Theyre going places, meeting people, doing stuff. Theyre wearing four and five hats and have to switch quickly. Theres almost no way to do all that if people are chained to their desks, yet theyre tethered to the responsibility [for the information on their PCs].
In short, handhelds equipped with the supporting software are enabling an ever-thinning workforce to do more with less time spent going back to central control room for no reason. No making phone calls when all you have to do was look at a screen, says Saucier.
What about the practical aspects of making a remote access system work? First, perhaps surprisingly, not every instance of a remote device needs to be ruggedized. The natural tendency is to think all these devices should be, says Jackson, but it all depends on exactly what youre using the device for.
For a portable measuring system that one guy is carrying around, you can buy a single, high-end, ruggedized, high-performance device, says Jackson, adding the caveat that ruggedization always adds size, weight and cost.
But if youre getting alarms on your cell phone, its a different matter. Remember that its your cell phone, advises Jackson. Its first purpose is to make calls. Making it ruggedized makes it less useful for its core purpose. The open communication protocols that PACs use allow the user to deploy standard, off-the-shelf hardwaresmart phones, PDAs, Toughbooks. They function well because theyre designed to be consumer devices. The idea is to enable people to see whats on that standard screen. If youre just trying to get alarms, a simpler, lower-cost, more readily usable device is better.
Still, there are places where ruggedization is essential. You cant take a run-of-the-mill BlackBerry into the refinery or factory. Even the Coca-Cola delivery guy uses a reggedized computer, because they get dropped, etc. If you bring them into a refinery, they have to be certified to work in hazardous areas, reminds Motorolas Eriksen. In some cases they have to be IS-certified.
That, of course, increases the cost of deployment, sometimes by an order of magnitude more than a consumer-grade device. But there are compromise approaches.
You can get something thats not much more than a commercial PDA or smart phone. Its what we call durable. Its not fully ruggedized, but it will last longer than a consumer-grade model. But heres the thing. Lets assume you dont really care if it breaks. Studies say that the total cost of ownership of a ruggedized device will still be less because youre going to get four or five years out of it, compared to a year or year and a half even if it doesnt break. One of the issues with a consumer model is that they get upgraded every 18 months.
That upgrade cycle is an important consideration for manufacturers considering rolling out handhelds to employees. They dont want to have to replace them every 18 months. Furthermore, ruggedized devices all have replaceable batteriesunlike many consumer models.
In the end, says Jackson, The PDA is an added bell and whistle. Its not a substitute for a standard SCADA/HMI. Now its hard to justify the cost of the PDA for all operators, but when the price keeps coming down, that becomes less of a disadvantage.
While real-time access to information for decision-making is the added-value carrot being dangled in front of potential customers, its important to remember that since many of the applications of handhelds in process operations have to do with recordkeeping and documentation, at some point or other, information gathered on the handheld will have to be synched up to the system of record.
Many implementations are untethered to a point, says Stephen Lambright, VP of marketing and customer service at wireless network system and services provider Apprion. At the end of the day, the connection to the system of record is remade. It gives some degree of portability. It makes information available to the person in the plant, even if it isnt in real time. It might be discontinuous, but its better than nothing.