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Designing Crane Controls with Applied Mechanical and Electrical Safety FeaturesThe use of overhead traveling bridge cranes in many varied applications is common practice. In particular, the use of cranes in the nuclear, military, commercial, aerospace, and other industries can involve safety critical situations. Considerations for Human Injury or Casualty, Loss of Assets, Endangering the Environment, or Economic Reduction must be addressed. Traditionally, in order to achieve additional safety in these applications, mechanical systems have been augmented with a variety of devices. These devices assure that a mechanical component failure shall reduce the risk of a catastrophic loss of the correct and/or safe load carrying capability. ASME NOG-1-1998, (Rules for Construction of Overhead and Gantry Cranes, Top Running Bridge, and Multiple Girder), provides design standards for cranes in safety critical areas. Over and above the minimum safety requirements of todays design standards, users struggle with obtaining a higher degree of reliability through more precise functional specifications while attempting to provide "smart" safety systems. Electrical control systems also may be equipped with protective devices similar to the mechanical design features. Demands for improvement of the cranes "control system" is often recognized, but difficult to quantify for this traditionally "mechanically" oriented market. Finite details for each operation must be examined and understood. As an example, load drift (or small motions) at close tolerances can be unacceptable (and considered critical). To meet these high functional demands encoders and other devices are independently added to control systems to provide motion and velocity feedback to the control drive. This paper will examine the implementation of Programmable Electronic Systems (PES). PES is a term this paper will use to describe any control system utilizing any programmable electronic device such as Programmable Logic Controllers (PLC), or an Adjustable Frequency Drive (AID) 'smart' programmable motion controller. Therefore the use of the term Programmable Electronic Systems (PES) is an encompassing description for a large spectrum of programmable electronic control devices.
Document ID
20020039704
Acquisition Source
Kennedy Space Center
Document Type
Preprint (Draft being sent to journal)
Authors
Lytle, Bradford P.
(NASA Kennedy Space Center Cocoa Beach, FL United States)
Walczak, Thomas A.
(Walczak (Thomas A.) Sugar Land, TX United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2002
Subject Category
Mechanical Engineering
Meeting Information
Meeting: Symposium on PLC In Safety Related Applications
Location: Cologne
Country: Germany
Start Date: May 7, 2002
End Date: May 8, 2002
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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