The Fermilab accelerator control system database

Abstract

Analog and digital signals from hardware in the field need to be transformed into user understandable information for display, monitoring, and control purposes at a Fermilab accelerator control console. The necessary information to do this translation is the basis of the information stored in the Fermilab Central VAX 11/785 database. The translation information must be retrieved with relatively little overhead via our own in-house network called ACNET. The limited address space of the PDP 11/34s used for driving the display and control consoles requires that a minimal amount of code reside in the console machines for database requests. Also the manner in which display applications tend to use information requires large packed arrays of information for as many as twenty or more devices in a single network request for a given console. An overview of the simple logical schema using the existing VAX/VMS indexed file organization is given. Also given is an overview of the attributes Fermilab has found necessary, through years of experience, for the display, monitor, and control of a hardware device. A description of the Central VAX 11/785 server process used to retrieve and pack information for the consoles along with a brief description of the console routines used for requesting information from the database is presented. Finally a discussion is given of the utility routines available for writing an application that can update the database or even generate special reports.