Going mobile? Things you should know

After working as a semiconductor process engineer, Hank Hogan hung up his cleanroom suit and now writes about process control and other technologies from Austin.

To paraphrase the old adage, putting a mobile device on an industrial network is all about security, security and security. Of course, it helps for the device and infrastructure to be rugged, reliable and have the right capabilities too.

Having a plan doesn't hurt either, says Christian Johansson, global product manager of 800xA asset management and device integration at ABB. The company makes a line of industrial wireless routers it uses in its products, including the 800xA control system family.

"Wireless solutions sometimes start in small scale and extend over time," Johansson says. "When defining a strategy, the big picture should, if possible, be considered, so the right technology and policies are defined at an early stage."

The security of the network is important, but so too is the infrastructure design. For instance, one choice would be to go with wireless access points, but that requires wiring each one individually. Alternatively, the infrastructure could be a wireless mesh network. In this approach, perhaps only one in 10 routers connects to the wired backhaul. The advantage of much less wiring has to be balanced against greater demands on the wireless network.

Ensuring that the infrastructure can deal with these demands is made easier if it supports diagnostic features such as Simple Network Management Protocol (SNMP) v3 and SNMP Traps, Johansson says. It's also vital that the network management system and software be able to handle prioritized virtual networks and personalized workspaces. The first of these allows different communication priority levels. In that case, highly important controller messages aren't slowed by something less important such as email.

SEE ALSO: How wireless communication is or isn't being used by machine builders

As for personalized workspaces and interfaces, they enable a network and automation system to tailor itself to the demands of a laptop, tablet or a smartphone. Thus, they allow the system to provide appropriate performance for differing classes of devices.

It's important to have the right type of network setup, says Barry Turner, sales engineering manager at industrial automation and networking solutions supplier Red Lion Controls. The company makes a line of regularly updated Wi-Fi radios specifically for industrial settings.

Industrial applications often don't require much bandwidth, Turner says. What they do need is high reliability. "The best way to provide a reliable Wi-Fi radio link is to use devices that support multiple-input/multiple-output (MIMO) communications," Turner says. "The use of MIMO will ensure that signals received from multiple paths, which is known as multipath, are put back together as they should be."

What's more, anything that produces a radio signal at either 2.4- or 5.8-GHz frequency can create wireless interference. A spectrum analyzer can detect possible interference.

Figure 1. When going mobile, consider system access, communication and, above all, security.

As for security, connections need to be encrypted, preferably using WPA2-AES for a Wi-Fi network, Turner says. Most Wi-Fi radios also support security based on the hardware address of the connecting client. This MAC-based security can be a good idea if combined with encryption of data.

Opto 22 doesn't make wireless mobile devices, but it does use them and works with end users adopting the technology. Application engineer Ben Orchard notes that multilayered security is a must. Mobile devices can be lost or stolen, so there's a need to institute passwords and passcodes. The latter is a minimum for any smartphone or tablet. There also must be a means to wipe, lock or locate a misplaced device.

In addition, there should be authentication and security at the application level, Orchard says. The first ensures users can't gain access to an application just by clicking on an icon. As for the second, the traffic to and from an application might take place over a variety of networks. Consequently, an application should use secure sockets layer (SSL) for communications.

As for the mobile device itself, ideally it needs to be able to function as intended in bright sunlight or dim shadow, as well as in high or low temperatures. Putting smart phones and tablets in cases and enclosures can help them withstand the often harsh environments and harsh treatment on plant floors, Orchard says.

He adds that this takes work, but the benefits outweigh any disadvantages. Mobile devices can function as gateways to a company's documentation, essentially putting an entire library in a pocket. In addition, they can photograph the results of processing on end products, which can help disposition of suspect product and correct errors. The camera that makes this possible can do even more to make things easier for end users. "The camera also doubles as a bar-code and QR reader," Orchard says.