Those of us who have been in fiber optics for a long time have gotten tired of hearing about the “advantages of fiber optics,” e.g., higher bandwidth, longer distance capabilities and immunity to electrical interference. But one application certainly effectively applies those capabilities of fiber: the industrial market.
We’re all familiar with the typical industrial environment. It’s big, hot in summer and cold in winter, dusty, and full of noisy equipment (acoustical and as electrical noise). Over the last few decades, most machines have become automated with computerized controls that send data back to computers that analyze and manage the factory floor. Video cameras monitor the activity of workers, machines and materials. Heating, ventilating and air conditioning (HVAC) systems have become computerized, in part, to improve the factory environment and to reduce energy costs.
Sometimes management doesn’t even know how much fiber is being used in a typical factory. Fiber Optics Association (FOA) board member Tom Collins, who also is a teacher for both a technical college and the International Brotherhood of Electrical Workers in Cincinnati, was asked to visit an auto factory to discuss a problem they were having with robots. The robots were welders, and they used plastic optical fiber (POF) along the arms for control. When the POF cables broke, it took weeks to get the high-priced replacements. Collins taught workers how to repair the cables themselves for a few bucks.
Automobile plants use fiber for welding robots, critical assembly and inspection tools, control of other machinery and the assembly lines. While he was there talking with the managers, Collins pointed out all the fiber on their factory floor that provided the communications for the factory management systems. This was not POF, of course, but regular glass fiber. However, he assured them their maintenance personnel could maintain, repair and troubleshoot the fiber themselves, saving considerable time and expense. Before he left, they asked him to come back and train their personnel.
Another FOA instructor, Doug Elliott, worked mostly with industrial customers, especially an aluminum smelter. Aluminum smelters are another place where fiber is popular because these facilities use extremely high electrical currents in processing the aluminum that interferes with other communications media.
Practically every industrial facility is the same. Besides fiber optic cables for communication, many of these facilities also use wireless devices. Fiber is ideal for connecting remote wireless access points in the noisy electrical environment.
Compared to local area networks (LANs) and data centers, most factories have modest data transmission needs, so the networks and links are slower than typical commercial buildings. Therefore, most links are multimode fiber, often older 62.5/125, that are longer than typical office links, and many systems use ST connectors since they are all metal, not plastic. Rugged cables, such as breakout or armored indoor types, may be used in areas where conduit is not available or easily installed. While most automation systems have direct fiber interfaces, there still is widespread use of copper-to-fiber media converters to allow older systems to use fiber optics.
What most factories have in common is large physical plants and a harsh environment. Regular copper cables are limited by their distance restrictions, susceptibility to electrical noise and degradation over large temperature swings. When computerized automation first started making inroads in factories, coaxial cable was the preferred medium, since it had more length capability and is less sensitive to electrical noise. However fiber has replaced even that because all systems now support fiber or even run exclusively on it.
Industrial fiber optic cable plants tend to require more protection than commercial buildings. Cables often are run in metal conduit, and terminations made in sealed enclosures. Pulling cable is usually no bigger problem than any other job, although the runs may be longer and have more corners, raising concern over pulling tension. Intermediate pulls and lubrication may be required. Cables are sometimes run along the roof and dropped to the floor location, so extra support for the vertical runs can be an issue.
Termination and splicing in an industrial environment can be a problem if the area is hot, cold or dusty. Really bad situations may mean working in a tent the outside plant installers use for splicing. Of course, planning ahead may make it possible to use prefabricated cabling.
Prefab cabling systems require good installation documentation to ensure the proper lengths of each cable assembly. Difficulties occasionally arise when pulling bundles of connectors through conduit. An alternative is to have only one end of the cable terminated and pull the unterminated end through the conduit. This works especially well when numerous cables connected to equipment on the factory floor are all pulled into a control room where the installer can set up and terminate all the cables at once.
HAYES is a VDV writer and educator and the president of The Fiber Optic Association. Find him at www.JimHayes.com.