Introduction

HISTORY OF CENTUM Twenty-four years have passed since the CENTUM was rolled out as the world’s first DCS in 1975. Up until now there have been several model changes. The first CENTUM had builtin microprocessors which at the time had begun to gather public attention as a technology offering great promise, and established the basic architecture of the CENTUM series in which the human interface and controllers are separated from one another and connected on a control bus. The first CENTUM introduced a new scheme, process operation and monitoring via CRTs and keyboards, to the world of process control. Present DCSs have inherited the basic architecture established by the CENTUMAs microprocessors advanced from 16-bit design to 32-bit design, Yokogawa released the CENTUM V in 1983 and the CENTUM-XL in 1988. Although at that time it was acknowledged that customers were dissatisfied with the fact that DCSs were closed systems, Yokogawa was focusing on incorporating into the CENTUM original devices and developing original operating systems and other software in order to gain better performance, by improving real-time controllability of controllers, increasing application capacity, and reducing the display retrieval time for the human interface. Each EOPS operator station, the human interface of the CENTUM-XL, was composed of up to 4 CRTs with 32-bit built-in processor, representing the best performance in those days