PPT On Scada And Dcs.ppt

PPT On Scada And Dcs.ppt

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  BY: Sahil Ahmad Roll no- 2100430519003 Bundelkhand Institute of Engineering & Technology Jhansi UP
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  DCS (Distributed ControlSystem) INTRODUCTION  Digital Control Systems(DCS) also known as Distributed Control System is the brain of the control system.  It is generally, since the 1970s, digital, and normally consists of field instruments, connected via wiring to computer buses or electrical buses to multiplexer/de multiplexers and A/D's or analog to digital and finally the Human-Machine Interface (HMI) or control consoles. A DCS is a process control system that uses a network to interconnect sensors, controllers, operator terminals and actuators. A DCS typically contains one or more computers for control and mostly use both proprietary interconnections and protocols for communications.  Control Systems are collectively named as "ICSS" Integrated Control and Safety System. Distinctly identified as "BPCS" Basic Process Control System. "SIS" Safety Instrumentation System. "F&G" Fire and Gas System.  DCS is employed in BPCS as well as used and prevalent control system.
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  DCS (Cont..)  TheDCS is a control system which collects the data from the field and decides what to do with them. Data from the field can either be stored for future reference, used for simple process control, use in conjunction with data from another part of the plant for advanced control strategies.  A distributed control system (DCS) is part of a manufacturing system.  Distributed control systems (DCS) are used in industrial and Chemical engineering applications to monitor and control distributed equipment with remote human intervention.
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  How does aDCS work?  In the field you have sensors and gauges that give and receive information. They convert this information into a electric signal that is sent to a control room somewhere in the field. This control room has programmed logic that is able to converts the signal into a pressure, flow rate, concentration, temperature, or level. This logic also contains the information that controls the process and takes the signal compares it with the set point sent from the operator may or may not be in the field and sends a signal to the manipulated variables in the field. The DCS covers all of the computer logic from the operator screen to the field box that contain the logic.
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  Shutdown systems  Shutdownsystem are the emergency setting of the logic to make sure the process can be contained and is environmentally safe. These setting are important for emergency response of the system. It is the job of the DCS to contain the logic for the shutdown system and be able to operate when a process exceed a certain limit.
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  DCS APPLICATIONS  DCSis a very broad term that describes solutions across a large variety of industries, including: * Electrical power grids and electrical generation plants * Environmental control systems * Traffic signals * Water management systems * Refining and chemical plants * Pharmaceutical manufacturing.
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  Distributed Control System
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  SCADA (Supervisory ControlAnd Data Acquisition) INTRODUCTION  As the name indicates, it is not a full control system, but rather focuses on the supervisory level. As such, it is a purely software package that is positioned on top of hardware to which it is interfaced, in general via Programmable Logic Controllers (PLC's), or other commercial hardware modules.  In reality, the primary purpose of SCADA is to monitor, control and alarm plant or regional operating systems from a central location. While override control is possible, it is infrequently utilized; however control set points are quite regularly changed by SCADA.  SCADA systems have made substantial progress over the recent years in terms of functionality, scalability, performance and openness such that they are an alternative to in house development even for very demanding and complex control systems.
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  Cont.. A SCADA applicationhas two elements:  The process/system/machinery you want to monitor a control - this can be a power plant, a water system, a network, a system of traffic lights, or anything else.  A network of intelligent devices that interfaces with the first system through sensors and control outputs. This network, which is the SCADA system, gives you the ability to measure and control specific elements of the first system.  You can build a SCADA system using several different kinds of technologies and protocols. This white paper will help you evaluate your options and decide what kind of SCADA system is best for your needs.
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  DCS vs. SCADAin Modern Environments  There is considerable confusion today about the difference between DCS ("Distributed Control Systems") and SCADA ("Site Control And Data Acquisition") systems. As you can tell from expanded acronyms above, SCADA includes "Data Acquisition" in addition to "Control". DCS, on the other hand, contains only "Control".  Understanding why this difference exists requires a 15-second history lesson. Historically, when computer networks either did not yet exist or had very low bandwidth, a SCADA system was the top-level controller for many lower-level intelligent agents. It was simply impractical to have a single system controlling every minute aspect of a system. In this technical environment, DCS devices did most of the detail work and simply reported to (and took high-level orders from) the SCADA system.
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  Cont…  Today, computernetworks have become so fast that there's no practical reason for SCADA and DCS to be separate. That's why they have blurred together into a single monitoring and control system. The choice of name - SCADA vs. DCS - largely depends on the region where you work. Some areas favor SCADA, others favor DCS. Occasionally, some people who worked with the systems before they effectively merged or who have moved from another region will use a term different than their coworkers. This again leads to confusion when new employees must learn to manage SCADA/DCS.
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  SUMMARY (SCADA vs. DCS) DCS is process oriented, while SCADA is data acquisition oriented.  DCS is process state driven, while SCADA is event driven.  DCS is commonly used to handle operations on a single locale, while SCADA is preferred for applications that are spread over a wide geographic location.  DCS operator stations are always connected to its I/O, while SCADA is expected to operate despite failure of field communications.
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  References  www.dpstele.com  www.pacontrol.com www.edaboard.com  www.instrumentations.blogspot.com  www.controlengeurope.com  www.differencebetween.net