Limit switches have been around for decades, protecting heavy equipment and providing important position information. They are used in everything from crane booms to gates, lifts to storage tanks — anywhere there is a need to sense the presence, absence or position of a moving object. In a crane application, the limit switch is located on the end of the boom. The limit switch could be used to indicate to the operator when the cable jib is close to the end of the boom and it is not safe to spool the cable further.
In the last few years, limit switches have become enabled by wireless using technologies such as IEEE 802.15.4 to transmit information from the remote switch to a receiver, which then converts the signal to ones used by standard controllers. Converting switch solutions to a wireless mode addresses a variety of customer needs for lowered cost and increased limit switch installation options, giving early adopters a competitive advantage in the design of next generation industrial and transportation equipment.
Benefits of Wireless Switching
Wireless limit switches can lower equipment costs in a variety of ways. For one, the cost of manufacturing and installation is reduced. Not only is the expense of wiring eliminated, there are no conduits, clips or connectors required to place a limit switch where it is needed. There are no wire routing problems to solve, no need for pulling wire during installation and fewer restrictions on location and placement of the limit switch.
Wireless limit switches can also reduce maintenance costs. Equipment wiring is less complex with the elimination of wired switches from the mix, simplifying troubleshooting and reducing commissioning time. Further, going wireless increases system reliability by eliminating the potential for having continuity issues with switch wiring or connectors. Switches also become simpler to replace, with no need to disconnect and re-attach wiring and no risk of incorrect wire attachment.
Global limit switches are an essential element of industrial and transportation controls, monitoring position and presence of doors, booms and valves. Conventional wired switches, however, present installation and maintenance challenges, especially in installations that are subject to harsh environments or involve frequent flexing in the wiring. In some cases, traditional wires can represent tripping hazards or can be compromised during normal equipment operation, thus causing expensive machine down-time.