SCADA is the acronym for Supervisory Control And Data Acquisition. In Europe, SCADA refers to a large-scale, distributed measurement and control system, while in the rest of the world SCADA may describe systems of any size or geographical distribution. SCADA systems are typically used to perform data collection and control at the supervisory level. Some systems are called SCADA despite only performing data acquisition and not control. It has been suggested that this article or section be merged with Backronym and Apronym (Discuss) Acronyms and initialisms are abbreviations, such as NATO, laser, and ABC, written as the initial letter or letters of words, and pronounced on the basis of this abbreviated written form. ... Measurement is the estimation of the magnitude of some attribute of an object, such as its length or weight, relative to a unit of measurement. ... For control theory in psychology and sociology, see control theory (sociology). ...

The supervisory control system is a system that is placed on top of a real-time control system to control a process that is external to the SCADA system (i.e. a computer, by itself, is not a SCADA system even though it controls its own power consumption and cooling). This implies that the system is not critical to control the process in real time, as there is a separate or integrated real-time automated control system that can respond quickly enough to compensate for process changes within the time constants of the process. The process can be industrial, infrastructure or facility based as described below: Real-time control is a popular term for a certain class of digital controllers. ... Realtime redirects here. ... Automation (ancient Greek: = self dictated) or Industrial Automation is the use of computers to control industrial machinery and processes, replacing human operators. ... Illustration of a physical process: a geyser in action. Process (lat. ...

• Industrial processes include those of manufacturing, production, power generation, fabrication, and refining, and may run in continuous, batch, repetitive, or discrete modes.
• Infrastructure processes may be public or private, and include water treatment and distribution, wastewater collection and treatment, oil and gas pipelines, electrical power transmission and distribution, and large communication systems.
• Facility processes occur both in public facilities and private ones, including buildings, airports, ships, and space stations. They monitor and control HVAC, access, and energy consumption.

Industrial processes are procedures involving chemical or mechanical steps to aid in the manufacture of an item or items, usually carried out on a very large scale. ... Manufacturing (from Latin manu factura, making by hand) is the use of tools and labor to make things for use or sale. ... Itaipu Dam is a hydroelectric generating station Electricity generation is the first process in the delivery of electricity to consumers. ... Fabrication may refer to more than one thing: Fabrication (metal) Semiconductor device fabrication Lie Fiction Fable This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Refining is the process of purification of a substance, usually used of a natural resource that is almost in a usable form, but which is more useful in its pure form. ... A water treatment plant in northern Portugal. ... Sewage treatment is the process that removes the majority of the contaminants from waste-water or sewage and produces both a liquid effluent suitable for disposal to the natural environment and a sludge. ... HVAC may also stand for High-voltage alternating current HVAC systems use ventilation air ducts installed throughout a building that supply conditioned air to a room through rectangular or round outlet vents, called diffusers; and ducts that remove air from return-air grilles Fire-resistance rated mechanical shaft with HVAC...

Systems concepts

SCADA systems, a branch of instrumentation engineering, include input-output signal hardware, controllers, human-machine interfacing ("HMI"), networks, communications, databases, and software. Human-Machine Interface (HMI) is a term that refers to the layer that separates a human that is operating a machine from the machine itself. ...

The term SCADA usually refers to centralized systems which monitor and control entire sites, or complexes of systems spread out over large areas (on the scale of kilometers or miles). Most site control is performed automatically by remote terminal units ("RTUs") or by programmable logic controllers ("PLCs"). Host control functions are usually restricted to basic site overriding or supervisory level intervention. For example, a PLC may control the flow of cooling water through part of an industrial process, but the SCADA system may allow operators to change the set points for the flow, and enable alarm conditions, such as loss of flow and high temperature, to be displayed and recorded. The feedback control loop passes through the RTU or PLC, while the SCADA system monitors the overall performance of the loop. A RTU, or Remote Terminal Unit is a device which interfaces objects in the physical world to a DCS or SCADA system by transmitting telemetry data to the system and/or altering the state of connected objects based on control messages received from the system. ... PLC A programmable logic controller, PLC or programmable controller is a small computer used for automation of real-world processes, such as control of machinery on factory assembly lines. ...

Image File history File links SCADA_schematic_overview-s. ...

Data acquisition begins at the RTU or PLC level and includes meter readings and equipment status reports that are communicated to SCADA as required. Data is then compiled and formatted in such a way that a control room operator using the HMI can make supervisory decisions to adjust or override normal RTU (PLC) controls. Data may also be fed to a Historian, often built on a commodity Database Management System, to allow trending and other analytical auditing. Data acquisition is the sampling of the real world to generate data that can be manipulated by a computer. ... A database management system (DBMS) is computer software designed for the purpose of managing databases. ...

SCADA systems typically implement a distributed database, commonly referred to as a tag database, which contains data elements called tags or points. A point represents a single input or output value monitored or controlled by the system. Points can be either "hard" or "soft". A hard point represents an actual input or output within the system, while a soft point results from logic and math operations applied to other points. (Most implementations conceptually remove the distinction by making every property a "soft" point expression, which may, in the simplest case, equal a single hard point.) Points are normally stored as value-timestamp pairs: a value, and the timestamp when it was recorded or calculated. A series of value-timestamp pairs gives the history of that point. It's also common to store additional metadata with tags, such as the path to a field device or PLC register, design time comments, and alarm information.

Complete SCADA systems or Distributed Control Systems ("DCS") may be acquired from a single supplier, but they are more often assembled from hardware and software components available from ABB, Allen-Bradley, DirectLOGIC, GE Fanuc, Omron, Schneider Electric, and Siemens PLCs, along with related HMI packages from Adroit, Citect, Control Microsystems, GE Fanuc,Honeywell, ICONICS, Inductive Automation, Rockwell Automation, Schneider Electric, SUPCON, Telvent, COPS[C-DAC open process Solution [C-DAC]COPS] and Wonderware. A distributed control system (DCS) refers to a control system usually of a manufacturing system, process or any kind of dynamic system, in which the controller elements are not central in location (like the brain) but are distributed throughout the system with each component sub-system controlled by one or... ABB, formerly Asea Brown Boveri, is a multinational corporation headquartered in Zürich, Switzerland, operating mainly in the power and automation technology areas. ... A Milwaukee-based company that specializes in industrial control and automation products. ... DirectLOGIC is a range of Programmable Logic Controllers produced by Koyo. ... GE Fanuc Automation, Inc, a joint venture between FANUC LTD. of Japan and General Electric, is a business unit of GE Industrial. ... OMRON is a Japanese electronics company in Kyoto, Kyoto. ... Kenny Acheson Schneider Electric is a French global company. ... Siemens redirects here. ... Citect is a software development company specialising in the Automation and Control industry. ... GE Fanuc Automation, Inc, a joint venture between FANUC LTD. of Japan and General Electric, is a business unit of GE Industrial. ... Honeywell Heating Specialties Company Stock Certificate dated 1924 signed by Mark C. Honeywell - courtesy of Scripophily. ... Rockwell Automation NYSE: ROK is an industrial automation company. ... Kenny Acheson Schneider Electric is a French global company. ... Telvent NASDAQ: TLVT is an information technology and industrial automation company specializing in SCADA, GIS and related IT systems for pipeline, energy utility, traffic and environmental monitoring industries. ... Wonderware is a supplier of industrial automation and information software solutions, having sold more than 400,000 software licenses in over 100,000 plants worldwide. ...

Human Machine Interface

A Human-Machine Interface or HMI is the apparatus which presents process data to a human operator, and through which the human operator controls the process. The user interface is the part of a system exposed to users. ...

The HMI industry was essentially born out of a need for a standardized way to monitor and to control multiple remote controllers, PLCs and other control devices. While a PLC does provide automated, pre-programmed control over a process, they are usually distributed across a plant, making it difficult to gather data from them manually. Historically PLCs had no standardized way to present information to an operator. The SCADA system gathers information from the PLCs and other controllers via some form of network, and combines and formats the information. An HMI may also be linked to a database, to provide trending, diagnostic data, and management information such as scheduled maintenance procedures, logistic information, detailed schematics for a particular sensor or machine, and expert-system troubleshooting guides. Since about 1998, virtually all major PLC manufacturers have offered integrated HMI/SCADA systems, many of them using open and non-proprietary communications protocols. Numerous specialized third-party HMI/SCADA packages, offering built-in compatibility with most major PLCs, have also entered the market, allowing mechanical engineers, electrical engineers and technicians to configure HMIs themselves, without the need for a custom-made program written by a software developer. Human-Machine Interface (HMI) is a term that refers to the layer that separates a human that is operating a machine from the machine itself. ... PLC & input/output arrangements A programmable logic controller (PLC), or programmable controller is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. ... This article is about computing. ...

SCADA is popular, due to its compatibility and reliability. It is used in small applications, like controlling the temperature of a room, to large applications, such as the control of nuclear power plants.

Hardware solutions

SCADA solutions often have Distributed Control System (DCS) components. Use of "smart" RTUs or PLCs, which are capable of autonomously executing simple logic processes without involving the master computer, is increasing. A functional block programming language, IEC 61131-3, is frequently used to create programs which run on these RTUs and PLCs. Unlike a procedural language such as the C programming language or FORTRAN, IEC 61131-3 has minimal training requirements by virtue of resembling historic physical control arrays. This allows SCADA system engineers to perform both the design and implementation of a program to be executed on a RTU or PLC. A distributed control system (DCS) refers to a control system usually of a manufacturing system, process or any kind of dynamic system, in which the controller elements are not central in location (like the brain) but are distributed throughout the system with each component sub-system controlled by one or... A RTU, or Remote Terminal Unit is a device which interfaces objects in the physical world to a DCS or SCADA system by transmitting telemetry data to the system and/or altering the state of connected objects based on control messages received from the system. ... IEC 61131-3 is a standard published in December 1993 by the IEC. It defines five PLC programming language standards: Ladder logic Sequential function chart Function block diagram Structured text Instruction list It is the third publication in the series IEC 61131. ... C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... Fortran (previously FORTRAN[1]) is a general-purpose[2], procedural,[3] imperative programming language that is especially suited to numeric computation and scientific computing. ...

System components

The three components of a SCADA system are:

1. Multiple Remote Terminal Units (also known as RTUs or Outstations).
2. Master Station and HMI Computer(s).
3. Communication infrastructure

For the Bobby Womack album, see Communication (1972 album). ...

Remote Terminal Unit (RTU)

The RTU connects to physical equipment, and reads status data such as the open/closed status from a switch or a valve, reads measurements such as pressure, flow, voltage or current. By sending signals to equipment the RTU can control equipment, such as opening or closing a switch or a valve, or setting the speed of a pump. A RTU, or Remote Terminal Unit is a device which interfaces objects in the physical world to a DCS or SCADA system by transmitting telemetry data to the system and/or altering the state of connected objects based on control messages received from the system. ... Electrical switches. ... // These water valves are operated by handles. ... A RTU, or Remote Terminal Unit is a device which interfaces objects in the physical world to a DCS or SCADA system by transmitting telemetry data to the system and/or altering the state of connected objects based on control messages received from the system. ... Electrical switches. ... // These water valves are operated by handles. ... This article is about a mechanical device. ...

The RTU can read digital status data or analog measurement data, and send out digital commands or analog setpoints. A RTU, or Remote Terminal Unit is a device which interfaces objects in the physical world to a DCS or SCADA system by transmitting telemetry data to the system and/or altering the state of connected objects based on control messages received from the system. ...

An important part of most SCADA implementations are alarms. An alarm is a digital status point that has either the value NORMAL or ALARM. Alarms can be created in such a way that when their requirements are met, they are activated. An example of an alarm is the "fuel tank empty" light in a car. The SCADA operator's attention is drawn to the part of the system requiring attention by the alarm. Emails and text messages are often sent along with an alarm activation alerting managers along with the SCADA operator.

Important to know that quality SCADA RTUs must have 3 important characteristics: Data Networking, Data Relaibility and Data Security.

Master Station

The term "Master Station" refers to the servers and software responsible for communicating with the field equipment (RTUs, PLCs, etc), and then to the HMI software running on workstations in the control room, or elsewhere. In smaller SCADA systems, the master station may be composed of a single PC. In larger SCADA systems, the master station may include multiple servers, distributed software applications, and disaster recovery sites. To increase the integrity of the system the multiple servers will often be configured in a dual-redundant or hot-standby formation providing continous control and monitoring in the event of a server failure.

The SCADA system usually presents the information to the operating personnel graphically, in the form of a mimic diagram. This means that the operator can see a schematic representation of the plant being controlled. For example, a picture of a pump connected to a pipe can show the operator that the pump is running and how much fluid it is pumping through the pipe at the moment. The operator can then switch the pump off. The HMI software will show the flow rate of the fluid in the pipe decrease in real time. Mimic diagrams may consist of line graphics and schematic symbols to represent process elements, or may consist of digital photographs of the process equipment overlain with animated symbols.

The HMI package for the SCADA system typically includes a drawing program that the operators or system maintenance personnel use to change the way these points are represented in the interface. These representations can be as simple as an on-screen traffic light, which represents the state of an actual traffic light in the field, or as complex as a multi-projector display representing the position of all of the elevators in a skyscraper or all of the trains on a railway. Initially, more "open" platforms such as Linux were not as widely used due to the highly dynamic development environment and because a SCADA customer that was able to afford the field hardware and devices to be controlled could usually also purchase UNIX or OpenVMS licenses. Today, all major operating systems are used for both master station servers and HMI workstations. This article is about operating systems that use the Linux kernel. ... Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®, sometimes also written as or ® with small caps) is a computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... OpenVMS[1] (Open Virtual Memory System or just VMS) is the name of a high-end computer server operating system that runs on the VAX[2] and Alpha[3] family of computers developed by Digital Equipment Corporation of Maynard, Massachusetts (DIGITAL was then purchased by Compaq, and is now owned...

Operational philosophy

Instead of relying on operator intervention, or master station automation, RTUs may now be required to operate on their own to control tunnel fires or perform other safety-related tasks. The master station software is required to do more analysis of data before presenting it to operators including historical analysis and analysis associated with particular industry requirements. Safety requirements are now being applied to the system as a whole and even master station software must meet stringent safety standards for some markets.

For some installations, the costs that would result from the control system failing is extremely high. Possibly even lives could be lost. Hardware for SCADA systems is generally ruggedized to withstand temperature, vibration, and voltage extremes, but in these installations reliability is enhanced by having redundant hardware and communications channels. A failing part can be quickly identified and its functionality automatically taken over by backup hardware. A failed part can often be replaced without interrupting the process. The reliability of such systems can be calculated statistically and is stated as the mean time to failure, which is a variant of mean time between failures. The calculated mean time to failure of such high reliability systems can be in the centuries. Mean time between failures (MTBF) is the mean (average) time between failures of a system, the reciprocal of the failure rate in the special case when the failure rate is constant. ...

Communication infrastructure and methods

SCADA systems have traditionally used combinations of radio and direct serial or modem connections to meet communication requirements, although Ethernet and IP over SONET is also frequently used at large sites such as railways and power stations. The remote management or monitoring function of a SCADA system is often referred to as telemetry. It has been suggested that this article be split into articles entitled Synchronous optical networking, SONET and Synchronous digital hierarchy. ... Telemetry is a technology that allows the remote measurement and reporting of information of interest to the system designer or operator. ...

This has also come under threat with some customers wanting SCADA data to travel over their pre-established corporate networks or to share the network with other applications. The legacy of the early low-bandwidth protocols remains, though. SCADA protocols are designed to be very compact and many are designed to send information to the master station only when the master station polls the RTU. Typical legacy SCADA protocols include Modbus, RP-570 and Conitel. These communication protocols are all SCADA-vendor specific. Standard protocols are IEC 60870-5-101 or 104, IEC 61850, Profibus and DNP3. These communication protocols are standardized and recognized by all major SCADA vendors. Many of these protocols now contain extensions to operate over TCP/IP, although it is good security engineering practice to avoid connecting SCADA systems to the Internet so the attack surface is reduced. Modbus is a serial communications protocol published by Modicon in 1979 for use with its programmable logic controllers (PLCs). ... RP-570 is a communications protocol used in industrial environments to communicate between a front-end computer and the substation to be controlled. ... IEC 60870-5-101 provides a communication profile for sending basic telecontrol messages between two systems, which uses permanent directly connected data circuits between the systems. ... IEC 61850 is an important international standard for substation automation that will have a very significant impact on how electric power systems are designed and built for many years to come. ... PROFIBUS (Process Field Bus) is the most popular type of fieldbus with worldwide more than 10 million nodes (2004) in use. ... DNP3 is a set of communications protocols used between components in process automation systems. ... The Internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet runs. ... Security engineering is the field of engineering dealing with the security and integrity of real-world systems. ...

RTUs and other automatic controller devices were being developed before the advent of industry wide standards for interoperability. The result is that developers and their management created a multitude of control protocols. Among the larger vendors, there was also the incentive to create their own protocol to "lock in" their customer base. A list of automation protocols is being compiled here. Automation Protocols This Wikipedia page was started to summarize all communication network protocols used for Building, Industrial and machine automation applications. ...

In latest days, the OPC or "OLE for Process Control" has become a wide an accepted solution for intercommunicating different hardware and software, allowing communication even between devices originally not intended to be part of an industrial network. OPC can stand for: Oligomeric proanthocyanidin OLE for Process Control OPC Foundation Orthodox Presbyterian Church Office of Policy Coordination This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ...

There are also other protocols like Modbus TCP/IP that became widely accepted and are now the standard for many hardware manufacturers.

Future trends in SCADA

The trend is for PLC and HMI/SCADA software to be more "mix-and-match". In the mid 1990s, the typical DAQ I/O manufacturer offered their own proprietary communications protocols over a suitable-distance carrier like RS-485. Towards the late 1990s, the shift towards open communications continued with I/O manufacturers offering support of open message structures like Modicon MODBUS over RS-485, and by 2000 most I/O makers offered completely open interfacing such as Modicon MODBUS over TCP/IP. The primary barriers of Ethernet TCP/IP's entrance into industrial automation (determinism, synchronization, protocol selection, environment suitability) are still a concern to a few extremely specialized applications, but for the vast majority of HMI/SCADA markets these barriers have been broken.

Security issues

Recently, the security of SCADA-based systems has come into question as they are increasingly seen as extremely vulnerable to cyberwarfare/cyberterrorism attacks on several fronts.^{[1] [2]}

In particular, security researchers are concerned about:

• the lack of concern about security and authentication in the design, deployment and operation of existing SCADA networks
• the mistaken belief that SCADA systems have the benefit of security by obscurity through the use of specialized protocols and proprietary interfaces
• the mistaken belief that SCADA networks are secure because they are supposedly physically secured
• the mistaken belief that SCADA networks are secure because they are supposedly disconnected from the Internet

Due to the mission-critical nature of a large number of SCADA systems, such attacks could, in a worst case scenario, cause massive financial losses through loss of data or actual physical destruction, misuse or theft, even loss of life, either directly or indirectly. Whether such concerns will cause a move away from the use of existing SCADA systems for mission-critical applications towards more secure architectures and configurations remains to be seen, given that at least some influential people in corporate and governmental circles believe that the benefits and lower initial costs of SCADA based systems still outweigh potential costs and risks.^{[citation needed]} Recently, multiple security vendors, such as Check Point and Innominate, have begun to address these risks by developing lines of specialized industrial firewall and VPN solutions for TCP/IP-based SCADA networks. In cryptography and computer security, security through obscurity (sometimes security by obscurity) is a controversial principle in security engineering, which attempts to use secrecy (of design, implementation, etc. ... Check Point Software Technologies Ltd. ... Innominate (from Latin innominatus meaning nameless) can refer to: The brachiocephalic artery The brachiocephalic veins The three large bones which form the hip bone Innominata, from the same root, is used in Substantia innominata, a part of the brain Iris innominata, a flower Category: ... Firewall may refer to: Firewall (construction), a physical barrier inside a building or vehicle, designed to limit the spread of fire, heat and structural collapse Firewall (networking), a logical barrier designed to prevent unauthorized or unwanted communications between sections of a computer network Firewall (film), a 2006 action film written... A Virtual Private Network, or VPN, is a private communications network usually used within a company, or by several different companies or organizations, communicating over a public network. ...

References

1. ^ D. Maynor and R. Graham. SCADA Security and Terrorism: We're Not Crying Wolf.
2. ^ Robert Lemos (2006-07-26). SCADA system makers pushed toward security. SecurityFocus. Retrieved on 2007-05-09.

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 207th day of the year (208th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 129th day of the year (130th in leap years) in the Gregorian calendar. ...

See also

• Industrial Control Systems
• Telemetry

Industrial control system (ICS) is a general term that encompasses several types of control systems, including supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other smaller control system configurations such as skid-mounted Programmable Logic Controllers (PLC) often found in the industrial sectors and critical infrastructures. ... Telemetry is a technology that allows the remote measurement and reporting of information of interest to the system designer or operator. ...

External links

• AlavuV2 Scada Open Source at Sourceforge.net