Controls improve safety, productivity and maintenance
By Bob Trebilcock, Editor at Large -- Modern Materials Handling, 2/1/2005
Columbus Coatings, an Ohio company that processes rolled steel for the automotive industry, relies on overhead cranes for its hot-dip production line. Over the years, however, the company saw an increase in breakdowns in the crane’s control systems, along with growing maintenance expenses. Problems obtaining replacement parts were sure signs that the controlling technology was out of date.
The solution was a custom-designed radio remote control system that integrates remote RF controls into a PLC platform (Control Chief Corp., 814-362-6811). The new system controls all crane functions from lightweight wireless transmitters. The flexible platform was designed to maintain important control characteristics based on crane inputs such as anti-collision devices and motor current sensors. “The new system provides ease of control, increased productivity and, most of all, unsurpassed safety,” says Jeff Sammons, maintenance manager. “I foresee a rapid return on our investment.” One important new feature is a “watchdog module” that provides a real-time, fail-safe means to shut the crane down in case of emergencies. The module continuously monitors critical control variables, like the processor, RF link, ladder logic program and the crane communications module. If any of the variables fail, the emergency stop shuts down the system in a matter of milliseconds. Sammons says that because the system uses an industry-standard PLC platform, training for maintenance personnel was minimal. The new control system is the first step in implementing a comprehensive wireless manufacturing information network. “The company will be able to install 2.4GHz wireless transceiver modules at any time to create a plug-in connection to monitor and maintain a log of critical maintenance data,” Sammons says. “This will permit the gathering of data for use in planning preventative maintenance schedules, running HMI software and a host of other functions.”
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