Content deleted Content added
No edit summary |
m Updated Reference 11 due to original link not being valid/available anymore. (ABB's website has been completely restructured.) |
||
| (9 intermediate revisions by 9 users not shown) | |||
Line 2:
{{Use British English|date=February 2018}}
{{Manufacturing}}
A '''distributed control system''' ('''DCS''') is a
Distributed control systems first emerged in large, high value, safety critical process industries, and were attractive because the DCS manufacturer would supply both the local control level and central supervisory equipment as an integrated package, thus reducing design integration risk. Today the functionality of [[SCADA|Supervisory control and data acquisition (SCADA)]] and DCS systems are very similar, but DCS tends to be used on large continuous process plants where high reliability and security is important, and the control room is not necessarily geographically remote. Many machine control systems exhibit similar properties as plant and process control systems do.<ref>{{Cite book |last=Eloranta |first=Veli-Pekka |title=Designing distributed control systems: a pattern language approach |last2=Koskinen |first2=Johannes |last3=Leppänen |first3=Marko |last4=Reijonen |first4=Ville |date=2014 |publisher=Wiley |isbn=978-1-118-69415-2 |series=Wiley series in software design patterns |___location=Chichester}}</ref>
==Structure==
Line 46:
* [[Chemical plant]]s
* [[Petrochemical]]
* [[Pulp and paper mill]]s (see also: [[Quality Control System QCS for paper, board and tissue machines|quality control system QCS]])
* Boiler controls and [[power plant]] systems
Line 88:
}}</ref>
In 1975, both [[Yamatake-Honeywell]]<ref>{{Cite web|url=https://www.azbil.com/corporate/company/history.html|title = Group History | Azbil Corporation Info | About the azbil Group | 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
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.
Line 104:
It was believed that if openness could be achieved and greater amounts of data could be shared throughout the enterprise that even greater things could be achieved. The first attempts to increase the openness of DCSs resulted in the adoption of the predominant operating system of the day: ''UNIX''. UNIX and its companion networking technology TCP-IP were developed by the US Department of Defense for openness, which was precisely the issue the process industries were looking to resolve.
As a result, suppliers also began to adopt Ethernet-based networks with their own proprietary protocol layers. The full TCP/IP standard was not implemented, but the use of Ethernet made it possible to implement the first instances of object management and global data access technology. The 1980s also witnessed the first [[programmable logic controller|PLCs]] integrated into the DCS infrastructure. Plant-wide historians also emerged to capitalize on the extended reach of automation systems. The first DCS supplier to adopt UNIX and Ethernet networking technologies was Foxboro, who introduced the I/A Series<ref>
===The application-centric era of the 1990s===
The drive toward openness in the 1980s gained momentum through the 1990s with the increased adoption of [[commercial off-the-shelf]] (COTS) components and IT standards. Probably the biggest transition undertaken during this time was the move from the UNIX operating system to the Windows environment. While the realm of the real time operating system ([[RTOS]]) for control applications remains dominated by real time commercial variants of UNIX or proprietary operating systems, everything above real-time control has made the transition to Windows.
The introduction of Microsoft at the desktop and server layers resulted in the development of technologies such as [[OLE for process control|OLE for process control (OPC)]], which is now a de facto industry connectivity standard. Internet technology also began to make its mark in automation and the world, with most DCS HMI supporting Internet connectivity. The 1990s were also known for the "Fieldbus Wars", where rival organizations competed to define what would become the IEC [[fieldbus]] standard for digital communication with field instrumentation instead of 4–20 milliamp analog communications. The first fieldbus installations occurred in the 1990s. Towards the end of the decade, the technology began to develop significant momentum, with the market consolidated around Ethernet I/P, Foundation Fieldbus and Profibus PA for process automation applications. Some suppliers built new systems from the ground up to maximize functionality with fieldbus, such as [[Rockwell Automation|Rockwell]] PlantPAx System, [[Honeywell]] with [[Experion]] & Plantscape [[SCADA]] systems, [[ABB]] with System 800xA,<ref>{{cite web|url=
The impact of COTS, however, was most pronounced at the hardware layer. For years, the primary business of DCS suppliers had been the supply of large amounts of hardware, particularly I/O and controllers. The initial proliferation of DCSs required the installation of prodigious amounts of this hardware, most of it manufactured from the bottom up by DCS suppliers. Standard computer components from manufacturers such as Intel and Motorola, however, made it cost prohibitive for DCS suppliers to continue making their own components, workstations, and networking hardware.
Line 138:
* [[EPICS]]
* [[Industrial control system]]
* [[Plant process and emergency shutdown systems]]
* [[Safety instrumented system|Safety instrumented system (SIS)]]
* [[TANGO]]
| |||