A methodology for string resolution

Abstract

In this paper we present a methodology, not a tool. We present this methodology with the intent that it be adopted, on a case by case basis, by each of the existing tools in EPICS. In presenting this methodology, we describe each of its two components in detail and conclude with an example depicting how the methodology can be used across a pair of tools. The task of any control system is to provide access to the various components of the machine being controlled, for example, the Advanced Photon Source (APS). By access, we mean the ability to monitor the machine`s status (reading) as well as the ability to explicitly change its status (writing). The Experimental Physics and Industrial Control System (EPICS) is a set of tools, designed to act in concert, that allows one to construct a control system. EPICS provides the ability to construct a control system that allows reading and writing access to the machine. It does this through the notion of databases. Each of the components of the APS that is accessed by the control system is represented in EPICS by a set of named database records. Once this abstraction is made, from physical device to named database records, the process of monitoring and changing the state of that device becomes the simple process of reading and writing information from and to its associated named records.