Tips and Tricks: 6 overlooked places to use industrial wireless
Technological advances like multiple-in-multiple-out (MIMO) transmitting and receiving are making Wi-Fi increasingly useful in industrial applications. Bandwidth and reliability have increased dramatically, and implementation costs have dropped. It’s worth rethinking some of the ways in which industrial data communications have been made in the past and considering where Wi-Fi can fit into the mix. Here are six overlooked locations to consider industrial wireless communications.
1. Flexible work cells
Industrial assembly was traditionally done by breaking down a process into individual steps and positioning machinery to maximize the efficiency and throughput of each machine. But that model lacked the flexibility needed for the production of small and customized lot sizes. The solution is the work cell, where the machinery and devices required for a specific project can be temporarily grouped together, and released for other uses as dictated by circumstances. But that means recabling the work cells every time there’s a change. Wi-Fi makes it easier, and cheaper, to set up and rearrange work cells.
2. Mobile connections
Cable connections don’t allow for much mobility. In applications like shipping and receiving, where the value of mobile machinery like forklifts is greatly enhanced if those devices have network connections, an industrial-grade Wi-Fi wireless access point (such as the APXG-Q5420 from B&B Electronics) can keep mobile equipment connected to the network even as it moves around a plant. A truck could connect to a forklift to download or upload delivery manifests and shipment details. Inventory systems, printers, scales, and other tools can communicate directly with a vehicle to expedite workflow. Wi-Fi clients like laptops, tablets, or smartphones can connect directly to the vehicle. Even vehicle maintenance is simplified, as onboard diagnostics and telematics can be monitored directly or from a remote location.
3. Network-enabling legacy devices
The enormous installed base of devices using serial communications isn’t going anywhere any time soon. But as newer protocols like Ethernet and Wi-Fi have appeared, it is becoming harder to find laptops or computers equipped with serial ports.
One solution is to equip serial devices with wireless Ethernet serial servers. Wireless serial server technology can turn a serial device into one more node on the network and give it communications capabilities that it was never designed to possess. A serial device could also be equipped with an embedded Wi-Fi access point module (like the APMG-Q551 from B&B Electronics), which creates a self-sustaining wireless hotspot much like the one at the corner coffee shop. Handheld Wi-Fi clients can then connect to it using Android, Apple iOS, or Microsoft Windows operating systems.
4. Cable vulnerability
Although network cables are commonly run under floors, or through walls or drop ceilings, some portion of the cable must eventually be exposed as it makes the final run to an attached device. That’s not a big issue in an office environment, but in industrial applications that final run leaves a cable vulnerable to serious damage. Cables may be crushed by moving machinery, stepped on, pulled, bent, or soaked in damaging fluids like solvents. And when cables fail, installing new cable is often cheaper and easier than tracking down the fault point in the existing installation. If this happens often enough it will ultimately create a confusing rat’s nest of old and new wiring.
The problem is magnified in temporary installations at remote locations. Imagine setting up a large generator system for a remote construction site, or to provide temporary power after a natural disaster. You’d need to tie together everything from supervisory control and data acquisition (SCADA) to Modbus network communications, and you’d be working in a slightly disorganized environment full of moving vehicles and workers. Murphy’s Law tells us what would happen to any exposed cable. Trenching your cable would help, but it would add time and expense to the project. And the final run would still be highly vulnerable. It would be easier to do the job with Wi-Fi.
5. Hard-to-wire locations
Sometimes you just can’t wire a widget. The expenses involved in running cable over a river or highway, for example, can be prohibitive. Even an indoor installation can be problematic, depending on where a device needs to be placed.
And moving data any significant distance over cable will call for expensive fiber optic cables, receivers, and transceivers. Fiber optic cable provides for enormous bandwidth and, as demonstrated by the telcos, it will carry data across entire continents. But how many applications would actually require that much range or bandwidth? For far less money you can install off-the-shelf Wi-Fi bridges (such as the Ghostbridge from B&B Electronics), which can create connections with speeds of up to 150 Mbps at distances of up to 15 km, depending upon local conditions.
6. Hazardous locations
In 1989 a solar flare created a magnetic storm that knocked out the power grid for all of Quebec, Canada, by inducing unexpected current on the power lines. Industrial motors and other high-power devices create magnetic fields that will affect nearby copper cabling in much the same way, though on a smaller scale. With luck, the only result will be data transmission errors and blue screens. But more serious events will damage expensive equipment.
And the greater the distance between connected devices, the more likely it becomes that communicating devices will be getting their power from different building ground references. When they do, copper cable can create a ground loop path. Again, you’ll be able to count yourself lucky if the only result is a blue screen.
These problems can’t be addressed with ordinary surge suppression, which only tries to limit spikes between the signal and ground line. (When the ground line rises, as it does in ground loop situations, surge suppression won’t stop it.) You could install isolators, which allow the lines to float while keeping the local side at the proper ground and signal level. And you could invest in fiber optics, which are natively immune to electromagnetic interference (EMI), spikes surges, and ground loops.
But if you’d prefer to save yourself some money and trouble, you could just use Wi-Fi.
– Mike Fahrion is data communications expert and the director of product management for B&B Electronics; Edited by Mark T. Hoske, content manager CFE Media, Control Engineering, Plant Engineering, and Consulting-Specifying Engineer. He can be reached at firstname.lastname@example.org.
About the author
Mike Fahrion, the director of product management at B&B Electronics, is an expert in data communications with 20 years of design and application experience. He oversees development of the company’s rugged M2M connectivity solutions for wireless and wired networks based on serial, Ethernet, wireless, and USB communication technologies. Fahrion is a speaker and author who writes a self-described politically incorrect newsletter, “eConnections,” with more than 50,000 monthly subscribers.