Editing Distributed control system (section)

===Origins===
Early [[minicomputer]]s were used in the control of industrial processes since the beginning of the 1960s.  The [[IBM 1800 Data Acquisition and Control System|IBM 1800]], for example, was an early computer that had input/output hardware to gather process signals in a plant for conversion from field contact levels (for digital points) and analog signals to the digital domain.

The first industrial control computer system was built 1959 at the Texaco Port Arthur, Texas, refinery with an [[TRW Inc.#Semiconductors and computers|RW-300]] of the [[TRW Inc.|Ramo-Wooldridge]] Company.<ref>{{cite journal
  |author1=Stout, T. M.  |author2=Williams, T. J.
  | title=Pioneering Work in the Field of Computer Process Control
  | journal=IEEE Annals of the History of Computing
  | year=1995
  | volume=17
  | issue=1
  | doi = 10.1109/85.366507
  | pages=6–18
}}</ref>

In 1975, both [[Yamatake-Honeywell]]<ref>{{Cite web|url=https://www.azbil.com/corporate/company/history.html|title = Group History &#124; Azbil Corporation Info &#124; About the azbil Group &#124; Azbil Corporation (Former Yamatake Corporation)}}</ref> and Japanese electrical engineering firm [[Yokogawa]] introduced their own independently produced DCS's - TDC 2000 and CENTUM systems, respectively. US-based Bristol also introduced their UCS 3000 universal controller in 1975. In 1978 [[Valmet]] introduced their own DCS system called Damatic (latest web-based generation Valmet DNAe<ref name="Valmet">[https://www.valmet.com/automation/control-systems/] [https://www.valmet.com/automation/control-systems/ Valmet Distributed Control Systems (Valmet DNAe, Valmet DNA, and Valmet D3)]</ref>). In 1980, Bailey (now part of ABB<ref>[http://www.abb.com/controlsystems] INFI 90</ref>) introduced the NETWORK 90 system,  Fisher Controls (now part of [[Emerson Electric]]) introduced the PROVoX system, [[Fischer & Porter Company]] (now also part of ABB<ref>[http://www.abb.com/product/us/9AAC115762.aspx] DCI-4000</ref>) introduced DCI-4000 (DCI stands for Distributed Control Instrumentation).

The DCS largely came about due to the increased availability of microcomputers and the proliferation of microprocessors in the world of process control.  Computers had already been applied to process automation for some time in the form of both [[direct digital control]] (DDC) and setpoint control. In the early 1970s [[Taylor Instrument Company]], (now part of ABB) developed the 1010 system, Foxboro the FOX1 system, Fisher Controls the DC<sup>2</sup> system and [[Bailey Controls]] the 1055 systems.  All of these were DDC applications implemented within minicomputers ([[Digital Equipment Corporation|DEC]] [[PDP-11]], [[Varian Data Machines]], [[MODCOMP]] etc.) and connected to proprietary Input/Output hardware. Sophisticated (for the time) continuous as well as batch control was implemented in this way. A more conservative approach was setpoint control, where process computers supervised clusters of analog process controllers. A workstation provided visibility into the process using text and crude character graphics. Availability of a fully functional graphical user interface was a way away.