Application programs and databases

Abstract

Each process control system demands its own set of application programs and possesses its own database. Simple process control systems require a modest volume of application programs — 2 kbytes (Miković, Internal Report No. 1651, Rade Koncar), whereas complex systems require 250 kbytes (Debeljuh and Vranić, 1982) or more. Many complex systems are split up into smaller functional systems since the cost of process control systems increases exponentially with program complexity (Laduzinsky, 1982). Application programs use program modules already developed, or macro-instructions, higher languages (e.g. FORTRAN, C, Pascal and Ada) of functional symbols (ASEA Information YLDA 78-08; STEP, Siemens). Some can be produced using different techniques, tested, linked together and tested again, but extended real-time programs are usually written in higher languages.