About the Author
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.
For industrial networks, the future holds more fiber and greater bandwidth. In the past, more fiberoptic cable would also have meant more headaches, since terminating a cable and connecting it has traditionally been a labor-intensive affair requiring special skills. However, advances have alleviated this problem and produced tougher and more easily installed cables, thereby allowing fiber to push deeper into industrial networks.
As this happens, it's important to realize in selecting an optical fiber that most of the cost lies in other network components, says Robert Reid. "It's really the electronics that dominate the cost. It's the transceivers that plug into the switches that dominate the cost."
Reid is senior product development manager at cabling and infrastructure manufacturer Panduit. Single-mode optical fiber, the type used in long-haul communications, is cheaper than the multimode fiber found in data centers and industrial networks. However, Reid says that a single-mode transceiver is at least three times the cost of the multimode version. Hence, in places where connections are plentiful and runs not too long, such as data centers and plant floors, a multimode fiber solution is less expensive overall.
No matter the fiber type, though, it must be protected from a plant floor environment that can include vibration, oils, temperature extremes and possible water washdowns. If many fibers are being run, the best solution might be to put them through a protective metal conduit. If only a handful of connections are needed, it might be best to use a metal armored cable.
Still better for such cases might be a protective plastic enclosure such as the electrician-friendly type introduced last year by Panduit. It is lighter than metal, offers a better bend radius and doesn't need grounding. As for terminating and attaching the fiber, that can be done in as little as 20 seconds by technicians using a special tool, according to Reid.
Another example of cable advances comes from optical fiber solutions provider OFS, which offers cabling specifically geared for the industrial market, according to Natasha Juhasz, market product analyst. For instance, consider its graded index hard-coat silica (GiHCS) fiberoptic products. Due to the gradually changing refractive index in the glass, signals come out cleaner as they travel down the fiber, which makes the data transmission rate faster in an industrial setting as compared to legacy step-index designs, says Juhasz. She adds that the resulting greater bandwidth is one reason why OFS cabling allows for communications to be more deterministic and closer to real time than the competition.
Like other optical cabling, the company's graded index fiber glass core is surrounded by a silica cladding and further encased by a hard and thin protective coating. The two play a role in setting the optical and mechanical characteristics of the fiber, as well as its plant floor ease-of-use.
"Our fiber is thicker. With a 230-micron diameter, it's noticeably easier to handle than traditional fibers with a 125-micron cladding," Juhasz says. For reference, human hairs are around 100 microns across.
Graded index polymer-coated fiber, the generic name for what OFS makes, is in the process of being made a part of connection standards set by ODVA, the automation networking technology industry group. Juhasz expects that to happen in 2015.
A third example of fiberoptic cable innovation comes from AFL, which engineers, makes and installs fiberoptic products and associated equipment. When it comes to industrial automation, Craig Stratton, AFL's business development manager for harsh environment fiberoptic cables, notes that what goes to a machine on the plant floor may need to be armored and meet fire-resistance ratings. AFL has an armored fiberoptic cable that is similar to the flexible metallic tubing used for copper.
AFL also has a new product that can be used in industrial settings. The Enterprise Air-Blown Cable solution consists of small-diameter optical fiber cable with as many as 48 strands of glass. This bundle can be sent through a microduct installed in a tray or a raceway or connected to a ceiling. It allows easy installation, according to Stratton.
"The cable can be jetted with an air-blowing system that can install the fiber at a rate of about 200 ft/min. It enables a facility to add a physical layer network as the need for bandwidth presents itself," he says.
