Information on DCS


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I am a student in an university.... I'm now working on an assigment on Distribute Control System ( DCS )....
Could anyone tell me what is DCS and where can I find more information about DCS... ???
DCS = Distributed Control System. Visit Micon on the web. You will be in contact with one of the best product.
Hello Haiman! Welcome to the
This question has been the topic for decades now in this website. Well, I will just paste what others have posted here before (thanks to these guys).

What is about DCS?
April 11, 2000, by Form China, Junfeng Zhou
Subject : Process Control
Text : What is DCS? Can you tell me ?

Re: What is about DCS?
May 02, 2000, by S Branley
DCS stands for Distributed Control System. Think of it as a bunch of computers connected by a network. Most Dcs use token ring as a communication protocol, examples include Baileys infi90 system and Honeywell's TDC3000. The wealth of tools and performance sets these systems apart from othe forms of control such as SCADA but that will all soon change.

Re: What is about DCS?
May 30, 2000, by Siramet Subpayasomboon
When you think about DCS, You may imagine about hundreds of single loop controller in a box called control unit of Field Control Unit. Function blocks such as PID need configuration work to assign the relation between each block.
Cascading between two PID blocks is a kinf configuration I said. Control station also have capability in sequence control but in second or half of second speed . Field Control Unit controls process via I/O modules. Normally
remote I/O of DCS is available. DCS is very good at availability and reliability. There are all level of redundancy from I/O level, I/O bus, power supply to CPU card. Every things will be its couple for backing up. You can contact function block ( for example , to change PID setting) in control unit via operator station that can be UNIX workstation , Industrial PC , Windows NT machine. Also on the screen of operator station , you will able to see your
process dynamically in form of graphic. Network that link all Control Stations and Operator Station normaly be redundant. Token Passing is very famous in large DCS.

The full thread is at "":

What's the difference between DCS & PLC?
June 01, 2000, by Daniel Wang
What's the difference between DCS & PLC?

Re: What's the difference between DCS & PLC?
June 25, 2000, by JM Giraud
DCS = Distributed Control System originally replaced analog controllers by numerical control software Replacing closed loops only. Progressively logic functions were added. The mother DCS was called "Intelligent Valve" developed by Powell Systems (?) around or in 1970.
PLC = Programmable Logic Controller (this word Controller is probably what mixes you up)were introduced shortly after the Intelligent Valve. They replaced relay racks. Progressively numerical closed loops were added. Today, their
mixed capabilities narrows the border line as some may be used solely for closing loops or performing solely logic.

The full thread is at "":
Distributed control system, its meaning is straitforward if you think about the name a little bit, it is a system that is distributed. Normally, the system has a central control unit (It could be a workstation or a central control panel), and other control devices distributed in a factory, a lab or other facilities. The central control unit communicate with the distributed control devices through LAN or Internet. Hence, the operator can operate the whole control
system through the central unit, and collect the data at the same time. It depends on what kind of information that you need, you can find information of vendors, softwares and hardwares on the internet.
Hope this will help.

Xin Liu
Vendors naturally have plenty of information to offer. Don't forget the ISA bookstore and their excellent 700+ page textbook "Understanding Distributed Processor Systems for Control" by Sam Herb. "":

Paul Gruhn, P.E., C.F.S.E.
Siemens, Houston, TX
Have you had any success with your search? I am looking for information about the same subject.

Best regards,