Remote Control: Material Handling at a Distance

With advances in digital technology, remote controls for material handling equipment are available at a lower cost than ever before. This is an especially attractive option for operating machines that, by their nature, present a certain degree of hazard.

More and more, remote control systems are beginning to appear in the workplace and one of the operations in which it's finding the most use is material handling. Chief among its benefits is that it offers operators the ability to control their machines from a safe distance. Not all material handling equipment is dangerous of course, and remote control has advantages for these other applications as well. Yet it's no secret that one of this technology's major selling points is that it significantly lowers the chances of injury to machinery operators as well as those who are working nearby.

Consider the case of crane operators. Sitting inside a crane's cab, the operator lacks a sufficient vantage point by which to control the crane alone. They must rely upon a second worker, outside the cab, to direct operations by using hand signals. In these situations there is always a chance of the operator misreading the signal and moving the crane erroneously, thus putting the operator, the signaler and anyone else in the vicinity, in danger. Remote control allows the operator and his coworkers to avoid this situation altogether. It also allows the operator to move freely around the crane load, easily stepping over and around obstacles, as opposed to having to stand at a stationary control point.

In addition to its safety advantage, the remote control of cranes makes sense economically. Since the operator is no longer required to stay inside the crane, a second worker is no longer needed for signaling. Removing the operator from the machine to work independently cuts labor costs and frees up manpower to use for other tasks. After numerous shifts, these savings begin to add up.

Remote control can be transmitted by either radio frequency (RF) signals or by infrared light. The use of RF signals is the decidedly more popular option in the U.S. where it accounts for approximately 98% of remote control transmissions. The RF signals used in remote control fall into two categories. There are narrow-band and spread spectrum systems, with narrow-band being sub-divided into high-power applications and low-power applications. Higher-power applications require a license from the FCC to use, but they have the advantage of providing a clear channel, free of static or interference from other users. This lends itself to safer control of the equipment. Using low-power frequencies, an operator runs the risk that directions will be interrupted. As for spread-spectrum systems, they do not require a license and have the additional benefit of offering two-way communication between the operator and the equipment.

Infrared remote control, by contrast, is more often used in Europe. Material handling experts cite a number of reasons why infrared remote control may actually be the better of the two technologies. The first reason being that because the infrared method works by transmitting a beam of light, the operator must be in full view of the crane he or she is operating. Once they are out of sight, the beam is obstructed and the controls turn off. This is an added safety factor, as the operator's full ability to see and assess the situation is critical. Another advantage of infrared remote control is that it is tuned specifically to the machine that it controls. This is helpful in situations where there is more than one piece of equipment that is outfitted for remote activity. With RF remote control there is a chance that a worker can pick up a control and accidentally start operating the wrong machine. Infrared remote control, because of the way it is tuned, makes this type of mistake impossible.

One of the keys to remote control's increased popularity is the fact that, through advances in circuitry, it can finally be made small enough to be easily handled. Fifteen years ago, remote control equipment of a single crane required an entire cabinet to contain. Now an operator can comfortably carry a remote control device on their person.

Another key to its popularity is price. Remote control is now available at a fraction of its former cost. This is due mostly to the cheaper cost of digital technology. Currently, an average piece of material handling equipment can be outfitted for remote usage for about $1,500 to $2,000. Companies should keep in mind that the complexity of the equipment in question can increase the price of installation significantly, with heavy-duty cranes running up to $6,000 and more complex projects demanding up to $30,000. And, although it is by no means the norm, some specialized remote control projects have cost up to $100,000 to install. Of course, all installation costs need to be factored in to the equation of how much a company will ultimately save by making the move to remote control. In most cases, taking the advantages of remote and its low cost into consideration, the savings it brings makes the switch worthwhile.

Source: Handling out of Harm's Way
Tom Feare
Manufacturing.net, March 1, 2001
http://www.manufacturing.net/articles/mmh/2001/0301/article12.html

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