Introduction to PLC and SCADA
Introduction to PLC's
Programmable logic controllers
Bedford Associates, founded by Richard Morley introduced the first programmable logic controller 1968. This PLC was known as the Modular Digital Controller MODICON which the company derived its name. The story of Howard Hendricks PLC said Dick Morley provides an interesting insight into the early development of PLC.
Schnieder Quantum PLC
Programmable Logic Controllers were developed to provide a replacement for Large relay control panels. These systems were inflexible require major wiring or replacement when the control sequence was to be changed.
The development the microprocessor from mid 1970 Programmable Logic Controllers have allowed to assume more complex tasks and larger features such as processor speed increases.
Ladder Logic
PLC had to be maintained by technicians and electrical maintenance personnel. To support this programming language Ladder developed. Ladder Logic is based on the technical relay contact symbols used diagrams for wiring through electrical control panels.
Until recently there has been no formal programming standard for the PLC. Introduction of the IEC 61131 standard in 1998 provides a more formal approach for encoding. PLC manufacturers have so far been slow in adopting the rule with partial application. The SearchEng articleIEC 61131-3, a standard for PLC Software by RW Lewis offers an introduction to the standard.
The documentation for the beginning of PLC Programs was either nonexistent or very poor, limited to simple routing and provide substantive comments, with large programs difficult to follow. This has been greatly improved with the development of PLC programming packages.
SCADA and HMI
PLCs interface with the principles of operator in much the same way as the relay control panel, by means of buttons and switches for the control and indicator lights.
Introduction personal computer (PC) in the 1980s allowed the development of computer-based interface for the operator, those who initially through simple control Monitoring and Data Acquisition (SCADA) and more recently dedicated by the operator control panels, known as human-machine interfaces (HMI).
The history of PLC
As Howard Hendricks told by Dick Morley
The following are some myths associated with the first ten years of the programmable controller business. These fables may or may not have a basis of truth, but in general, are the best that my memory fraught Alzheimer can be done this time. As has often been in other articles and reports, implementation and Modicon programmable controller industry as a whole is well documented. The controller programs are detailed in the New Year's Day 1968, and from then until now, slow growth and enabled the manufacturing and process control for benefit-oriented software applications.
The first few days however, is not straightforward or simple. We had some real problems in the first days to convince people that a software box, although coated cast iron, could do the same thing as 50 feet of cabinets, relays and associated wiring. The process was really hard, and deserves some of the stories that I hope the reader is presented with as it moves forward through the swamp of my twisting mind.
One of my first recommendations was that the programmable controller, according to my own system architecture specification, not need to go fast because I felt as if the speed was not a criterion, as it would go as fast as was necessary. The initial machine, which was never delivered, there were only 125 words of memory, and speed was not a criterion as mentioned above. You can imagine what happened! First, immediately ran out of memory, and secondly, the machine was too slow to perform any function anywhere near the response time of the relay. Liaison response times exist in the order of 1/60th of a second, and the topology consists of many cabinets full of relays becomes code is significantly more than 125 words. We extended 1K memory and from there to 4K. At 4K, that was the test of time for a good time. Initially, marketing and memory sizes were sold in 1K, 2K, 3K, (?) And 4K. 3 K was obviously 4K version with limited direction so that the expansion of 4K field could be done easily.
The question of speed, in part, was part of the initial designs. No interruptions were necessary because the conditions of the external signal were written directly in memory without any supervision requirements or operating system of conventional type. This allowed the processor to pay attention to the logical solution cleaning in place of the E / S. As a result, of course, the processor had to have more processing power normally associated with this size team, and secondly, the system had to be made to run fast.
We've increased the memory size, as mentioned above, but to get it to run quickly, we had to break the machine in three different components. Initially, the programmable controller was designed for a processor board and a memory, and manipulation algorithms and logic that would be done in software. This approach was very slow, both in the generic equipment "purchased in the store, and other items.
We did, however, manage to substantially speed machine by third principal component. This is called the logic solver. On board the dominant logic solver to solve the algorithms associated with the solution of the ladder without the intervention and classical approach to general purpose software processing. This meant we ended up with three cards, memory, logic and process solutions. This step allowed us get the speed we needed in this specific application computer to solve the problem of simple perception of several closets full of wiring the relay.
We had also taken a modular approach to the programmable controller. At the event, the name means Modicon Modular Digital Controller. Modularity, however, soon abandoned because, as everyone knows, open architectures are not good. Instead, marketing was the premise that a large footprint, would in itself all the problems you want solved. This means that a purchaser of programmable controllers could buy a large number of these units, and software and hardware would be identical in a wide range of applications in its plant. Service, maintenance and total cost of living would be substantially less than the perceived lower cost of an architecture open and modular expansion. Although initially a supporter of open architecture modular expansion, soon convinced by the market, but this was crazy.
We took one of our first units, which was intended for the machine tool industry by Bedford Associates consulting my background, until one of the applicants in early of this equipment. This particular applicant was Byrant early Chuck and Grinder in Springfield, Vermont. We take the machine up there, and was heavy. This was the 084. The 084 was in the trunk of my old Pontiac, and since she needed help carrying it, asked some people to help Bryant. We went out and opened the hood and the first comment made by a programmable controller external observer, said, "Thank God it, s no color is another piece of pie plate.
We hypothesize this comment in particular that the robustness of visual design was nice for him, and humans (unlike Mars), means that this attitude was the depth of the building machine, both hardware and software. In fact, this was the case, and the machine as a result, was built rugged, did not have the switch ON / OFF, had no followers, make no noise and had no wear on the system.
To remember for a moment — in the selection of nuclei of the first memories, which in itself himself was a revolutionary step, these nuclei were selected and applied Shannon s law. Shannon, s the law assumes that the signal to noise ratio makes signals good or bad. There are several ways to get the power of the signal to noise ratio, a code is largely to be triply redundant, and much use and a lot of testing errors. There is another way, which is perfectly compatible with the theory, which is used a lot of signal strength in another domain. A nice change, a battery Car and D-sized bulb work quite well for a long time period.
So what we did was instead of going verification errors, triply redundant and stuff, what we have, and sought and found high-energy, large ferrite core memories had a lot of energy by bit. We still make the same assumption today. The energy per bit is very important — as Shannon, the theory s said in his most famous article of 1948 noise the signal to noise power is what gives the transmission. how is the signal strength was to increase the energy per bit. This is what I felt was much more important to get the energy per bit increased by double that is transmitted. But I digress. Bryant Grinder Chuck and sets, and I liked the team that you never bought one. In turn, he thought it was a good idea, as many did at the time, tried to develop their own.
One of our major customers First, however, was in Landis Landis, PA. The team flew on a private plane, and with apprehension, because we arrived late (as usual), brought the team to Landis. In this way, she tripped over the threshold. The KA-RASH team was on the floor! Without much displeasure, we picked the team up, rolled in. hooked up, and low and behold that worked pretty well.
Now, Landis was pleased and surprised. They were happy because it worked, but what pleasantly surprised — Not because the team worked — but because the guys from Modicon full confidence in the team to work even though they are losing. In other words, people were not Modicon, t nervous about the fact that it fell above the threshold.
Landis took it and then wrapped the welding wire coils around to induce electromagnetic noise machine to see if they could make it fail. I was there! Was used to test the programmable controllers with a Tesla coil which affected a quarter inch to half inch bow in any part of the programmable controller system and still had to continue to run. There was significant relationship strangeness programmable controller. For example, had no on / off switch. He had no means to load software. He had fans. It worked well. Could survive bad, physical and thermal. It was not standard in the computer industry. There were many things that are more difficult in the acceptance of the programmable controller, and early acceptance was more difficult.
Our sales in the first four years were abysmal. In the early innovators like Landers and General Motors, of course, the heroes our eyes, but would buy a small number of units and then test them on the field before committing themselves further. We had one customer in the business of business public service that took them about six to seven years to make the decision, but the first.
Never really sold Programmable Controllers on the market in question, which was the control of machine tools such as lathes, grinders and stuff, but we, as luck would have it, run into the market transfer line was and remains the main long-term market for the application of programmable controllers. discrete parts manufacturing environments automatic, ie, mass production, it remains, and will probably be for the future, the mainstay of the programmable controller industry.
Some of the most interesting stories center around the personalities and experiences as opposed to the programmable controller. Modicon, s third president (or fourth if you count my two weeks of the season) was Don Kramer. When Mr. Kramer was elected president, decided to go out and celebrate in Lanum Club in Andover. At the same time, we feel that we should celebrate more than two martinis and food. When we left the tent for the Club Lanum, Don put aside the comment that "the place is dirty and needs a paint job. When we were leaving, I mentioned to Don that as president he has to change what you say, and not very open — has to be a bit careful with what they say because employees, customers, and the boards tend to take what he tells the truth. Instead of listening to the truth, listen to the literal statements, and we must be careful. We went to the Club Lanum bright and had a good two hours of debate, food and drink. In return, when we entered the lobby Modicon, we realized that there was scaffolding on painting and people. Lou went and asked why these people are painting, because, at that time, we do not, I have no money. Who ordered this painting? And Lou looked Don Kramer straight in the eye and said, "Why did Mr. Kramer. Nuff said.
As mentioned many times, its author, who, I s — — Dick Morley is supposed to be the inventor of the PLC. This is the best, partially true. What made the company and the Modicon programmable controller off the 084 was not, but the 184. The 184 was made in the design cycle of Michael Greenberg, one of the best engineers I've known. He and Lee Rousseau, president and marketeer, came up with a specification and a design that revolutionized the business of automation. 184 was built over the objections of your server. I was a purist and considered all the bells and whistles and were not things, not pure, and somehow were contaminating my "glorious design, Dead wrong again, Morley! were specifically Now! the 184 was a walloping success, not the 084, — not the invention of the programmable controller — but a product designed to meet the needs of market and customer, called 184 and took off and Modicon programmable controller of the company and the industry it is today. My congratulations to the two chefs — Lee and Mike Rousseau Greenberg.
The issue of quality of programmable controllers is a story that is often taken for granted. The gentle reader should remember that our engineering people is the computer industry, where reliability in those days was a ghost a ghost — design, a ghost of the costs. People felt that the reliability was something that other people did, and that if we could only deliver faster computers, but they gave us, work does not, everything would be fine.
When programmable controller was designed, was designed to be reliable. We used a large amount of energy per information bit to the use of components of D-sized, memory large nuclei, relatively stable and large prints on printed circuit boards and systems totally closed and conductive cooling. No fans were used, and outdoor air was not allowed to enter the system for fear of contamination and corrosion. Mentally, I had imagined the programmable controller is in back of a truck, outdoors, and being driven all around Texas — led, led around Alaska. In these circumstances, anted to survive. The other requirement was that he was on a pole to help run a utility or a microwave station that was not climate controlled, and they are not provided at all. In these circumstances, would work for the year was meant to be? Could it be walled in? Could it be screwed into a system that is expected to last 20 years?
The comic side of this is when we did all the designs and carefully tried to make this system as inherently reliable as we could, not by layoffs, but construction also. In other words, was designed to be built, was designed to be designed, and was designed to be reliable. We, however, as engineers, do not you, do not understand counters and manufacturing. both have their grail, shipping later this month. As far as we could ascertain at the time, shipments were made independent of quality, independent of whether the system worked.
In the early days of Modicon programmable controller, although I was not, ta direct employees and an owner, I would give my phone number from your home to many of our customers so that if critics had a problem, I can call directly. Multiple calls notes that when sent near the end of the month, say octubre 34th, the team would not be presented, and secondly, when opened the box and took the machine away, cards were missing, the bolts are at the bottom of the cabinets, and some of the cards were not fully inserted. In other words, that the end of the month was much more important to deliver equipment running. put it mildly, they were angry! How do we as engineers to maintain quality without continuous monitoring, which is more difficult to design and entrepreneurship. What we did was to specify and design "blue boxes. These were cabinetries that the system had to run and run continuously for a minimum of 24 hours under load, and in various conditions. The box was made of wood, but she wished cycle heat input programmable controller in several / output loads. He also ran as a specification, a coil Tesla was to be used in the programmable controller, and that the vibration and shock with a hammer (rubber) would be part of the specification.
This may seem unscientific many of you, but suppose you try to get your computer running while someone deliberately tries to destroy it with a rubber hammer or spark coil you can put anywhere in the system. Remember that your intention is to stop the processor. This combination significantly depressed monthly shipments during the first period. As a result, however, the message got through. We not only build kilns and evidence, and pay attention to heat and spark and RF emissions, there would be the system continuously even in the crate to get the maximum number of hours before as we could. It was important for us that we errors and not the client and the client side.
The language itself, Lister staircase bears some discussion. This particular language was not Modicon invention. Our hypothesis is that the language is very old, and originated in Germany to describe the circuitry of the relay. If you look lister ladder, it has been our technical community for so long, somehow we think those really look like little symboligies relays. In fact, it, sa way based language mnemonic standards, very modern and very high level, but designed in a Darwinian fashion over a period of several decades.
Ladder logic construct "If … Then … is a powerful construction currently used in expert systems and other rule-based languages. The symbolism, allowing normally open and normally closed as well as serial and parallel situations representation was used for many decades before the invention of the programmable controller. I have worked on machines where the number of size C and D size prints were hung on special racks, and it would be up to three feet thick value of documentation Drawing on cases.
The staircase name comes from the fact that, on the right of the drawing is a line of tension and the left hand line voltage from others, and in the middle of a horizontal, is the statement or connection sequential logic elements we call relays or relay logic. The first 084 had only logic functionality, and as a result was marginal. In other words, all we did was to replace the relays instead of improving functionality by a factor of ten, which is the business rule. Immediately, of course, based on customer response and our own frustrations, put it in the language List steps such as addition, multiplication, subtraction, and other features that went far beyond the capacity of relief and entered the realm of mathematics and theory sets. This was not enough, however, and we need some way to make a "call to a symbolic" ladder subroutine lister and representation.
A software engineer, Chuck Schelberg, and I were in the conference room of a day trying to figure out how we can make a generic call functionality which greatly exceeded the symbolism of the relay and representation, and went with the "DX. This function is a function block to be an element in the ladder representation that could perform many functions including matrix, the drive motor functions, functions servo, extended math functions, PID loops, ad nauseam. We feel that there would be occasional representation and use of these features, and that's not much that done to separate programmable controller to modify the software. Wrong again!
The first customer took delivery of a programmable controller using the function DX had a capacity to be predictable and operate in real time. RUN light went out, and time to run a full scan or processing logic ladder were beyond the time allowed. Each line had a unique role DX on it. Once again we learn that when improving the functionality, people use it. I've never designed a team that had too much memory. I've designed so that computers only have very little memory. The same applies to any other functionality. The conventional wisdom seems to think the price / performance depends on one thing — money — when, in fact, my experience has been that the poor customer cares about the price.
This price / performance that is lying on one of the lessons we have learned is that customers want the functionality of the cost complete life cycle of the installation jobs. the client also wants to facilitate the installation, have a good time, and to be proud of the work you do. After he, s done, he never wants to come back .. The team should work as installed and as a basis. At one point, while the programmable controller before failure in the area was 50,000 hours. This is far above almost any other electronic or computer control.
The concept of languages and high level languages is important. The programmable controller, as it evolved, he began to ask more and more power, more and more memory. Memories rose continuously and as power. It is estimated that at the same time, the mid-1970s, the programmable controller had the equivalent of two processors MIPS and 128 kilobytes of memory, in that time was a minicomputer power capacity significantly. Why? high-level languages need energy to function. If we take the equivalent of the ladder lister statement "If … Then … the high-level language, represented here requires a substantial amount of compiler performance, if you will, underlying code generation. In other words, this statement generates the underlying code to be executed quickly, safely, and contain within them, all aspects of resource allocation and resource operations. The highest level is the language, the most powerful processor apparently has to be run to language. Straight Lister is a high-level language based on rules that, until now, shelter, did not talk much about in these terms. Our clients deal with the programmable controller as a relay box, and well they should. the theory of language is neither necessary not desirable for most customers meet. Customers, however, understand your problem, and indeed are much more intelligent than the design engineers, because the dimensions of the problem far exceed the relatively simple problem of designing a software system and language. Lister ladder requires high performance is one of the reasons why you have difficulty running on the PC, even today
INTRODUCTION TO SCADA
SCADA stands for Supervisory Control and Data Acquisition. Usually refers to a system industrial control: a computer system monitoring and control of a process. The process can be industrial, infrastructure or facility based as described below:
Industrial processes are the manufacturing, production, power generation, manufacturing and refining, and can operate continuously, batch, repetitive, or discrete modes.
Infrastructure processes may be public or private and include water treatment and distribution, and wastewater, pipelines, electricity transmission and distribution and large communication systems.
Ease processes occur in both public and private facilities such as buildings, airports, ships and space stations. They monitor and control HVAC, access and consumption energy.
A SCADA System usually consists of the following subsystems:
A Man-Machine Interface or HMI is the apparatus which presents process data to a human operator, and through which the human operator controls, and controls the process.
A control (PC) system, the collection (Acquisition) data on the process and sending commands (control) for the process
Remote Terminal Units (RTU) that connects to sensors in the process, converting sensor signals into digital data and digital data transmission to the control system.
Communication infrastructure connecting the control system to the remote terminal units
There are, in several industries, considerable confusion about the differences between SCADA systems and distributed control systems (DCS). In general, a SCADA system usually refers to a system that coordinates, but does not control real-time processes. The debate on real-time control is a bit clouded by the latest telecommunications technology, enabling reliable latency, low, high-speed communications in areas extensive. Most differences between SCADA and DCS distributed control system are culturally determined and tend to be ignored. As communication infrastructures more capacity available, the difference between DCS and SCADA will vanish.
Systems concepts
The term SCADA usually refers to centralized systems to monitor and control entire sites, or complex distributed systems in large areas (Anything from an industrial plant and a country). Most control actions are performed automatically by remote terminal units (RTU) or programmable logic controllers (PLC). Host control functions are usually restricted to the baseline urgent intervention or supervision. For example, a PLC can control the flow of cooling water through part of an industrial process, but the SCADA system may allow operators to change set points for flow, and enable alarm conditions, as the loss of pressure and high temperature to be displayed and recorded. The feedback control loop passes through the RTU or PLC, while the SCADA system monitors overall performance of the loop.
Data acquisition begins at the RTU or PLC level and includes meter readings and status reports teams that are communicated to SCADA as required. The data are compiled and formatted so that a control room operator using the HMI can control decisions adjust or override normal RTU (PLC) controls. The data can also be fed to a historian, often built on a database management system products Basic to allow the trend and analytical audit.
SCADA systems typically implement a distributed database, commonly known as a tag database, which contains data elements called tags or points. A point represents a single input or output value monitored or controlled system. Points may be "hard" or "soft." A sticking point is a real input or output within the system, while a soft spot results logic applied mathematics and operations to other points. (Most implementations conceptually remove the distinction by making every property a "soft" Points point of expression, which may, in the simplest case, representing a single hard point.) Normally pairs are stored as timestamp value: a value and the date and time it was recorded or calculated. A series of pairs of brand value of time gives the history of this point. It is also common to store additional metadata with labels, as the path to a field device or PLC is registered, comments on design time, and alarm information.
Interface Man-Machine
A Man-Machine Interface or HMI is the apparatus which presents process data to a human operator, and through which the human operator controls the process.
An HMI is usually linked to databases and software programs SCADA system, to provide analysis of trends, diagnostic data and information management, such as scheduled maintenance procedures, logistic information, detailed schemes for a particular sensor or machine, and the system of expert troubleshooting guides.
The HMI system usually presents the information to operations personnel graphically in the form of a summary table. This means that the operator can view a schematic representation of the plant being controlled. For example, a picture of a pump connected to a pipe may pose the operator that the pump is running and the amount of fluid is pumped through the pipeline at the moment. The operator can change the pump. The HMI software will show the flow of fluid in the pipe decrease in real time. Mimic diagrams may consist of line graphics and symbols schema to represent the elements of the process, or may consist of digital photographs of the process equipment is covered with animated symbols.
Package HMI for SCADA system typically includes a drawing program for operators or system maintenance personnel use to change the way these points are represented on the interface. These representations can be as simple as a traffic light on the screen, representing the state of a real light in the field, or as complex as a screen multi-projector that represents the position of all elevators in a skyscraper, all trains on a railroad.
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 so that when their needs are met, 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 system that requires the attention of the alarm. E-mails and text messages are often sent along with an activation warning alarm with administrators SCADA operator.
Hardware Solutions
SCADA solutions often have Distributed Control System (DCS) components. The use of "smart" RTUs or PLCs, which are capable of running autonomously simple logic processes without involving the master computer, is increasing. A programming language functional block, IEC 61131-3, is frequently used to create programs that run on these RTUs and PLCs. Unlike a procedural language, as the programming language C or FORTRAN, IEC 61131-3 has minimal training requirements, under such historic physical control arrays. This allows a SCADA system engineers to perform both the design and implementation of a program running on a RTU or PLC. From about 1998, practically all PLC manufacturers have offered major HMI / SCADA, many of them using open communication protocols, not owners. Numerous specialized third-party HMI / SCADA packages, offers built-in compatibility with most major PLCs, have also entered the market, allowing mechanical engineers, electrical engineers and technicians to HMI configuring themselves without the need for a customized program written by a software developer.
Remote Terminal Unit (RTU)
The RTU connects to physical equipment. Usually, an RTU converts electrical signals from computers to digital values, such as the status of open / closed a switch or valve or measures such as pressure, flow, voltage or current. By converting digital benchmarks into electrical signals and shipment of these electrical signals to equipment the RTU can control equipment such as open or close a switch or valve, or set the speed of a pump.
Quality SCADA RTU have these characteristics:
Data Network Capacity
Reliability data
Data Security.
Surveillance Station
The term "monitoring station" refers to the servers and software responsible for communicating with the field equipment (RTUs, PLCs, etc), then the HMI software running on workstations in the room control, or elsewhere. In smaller SCADA systems, the master station may be composed of a single PC. In larger SCADA systems, station principal may include multiple servers, distributed software applications, and disaster recovery sites. To enhance the integrity of the system of multiple servers often be configured for dual training or hot standby redundancy, providing continuous monitoring and supervision in the case of a server failure.
At first, more "open" platforms such as Linux, were not as widely used due to highly dynamic development environment and because a client SCADA was able to afford the field hardware and devices usually can be controlled also purchase UNIX or OpenVMS licenses. Today, the main systems operations are used for both servers and workstations HMI station chief.
Operational philosophy
In some facilities, the costs that would result from the lack of control system is extremely high. Possibly even lives could be lost. Hardware for some systems SCADA is solidly to withstand temperature, vibration, and extremes of stress, but most critical facilities reliability is improved by having hardware redundant communication channels, to the point of having multiple control centers are fully equipped. A party can not be identified quickly and automatically functionality assumed by the backup hardware. A party can often be replaced without interrupting the process. The reliability of these systems can be calculated statistically and is stated as the average time to failure, which is a variant of mean time between failures. The estimated mean time to failure of these highly reliable systems can be of the order of centuries.
Communication infrastructure and methods
SCADA systems have traditionally used combinations of radio and direct serial or modem connections to meet communication needs, although Ethernet and IP over SONET / SDH is also frequently used on large sites, such as railways and power plants. The remote management or control of the function of a SCADA system is often referred to as telemetry.
This also has been threatening to some customers who wish to SCADA data to travel on pre-established corporate networks or to share the system with other applications. The legacy of the first protocols for low bandwidth remains, however. SCADA protocols are designed to be very compact and many are designed to send information to the station principal only when the master station polls the RTU. Typical legacy SCADA protocols include Modbus RTU, RP-570, Profibus and Conitel. These communication protocols are SCADA-vendor specific, but are widely adopted and used. Standard protocols are IEC 60870-5-101 or 104, IEC 61850 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. It's a good safety engineering practice to avoid connecting SCADA systems to the Internet so the attack surface is reduced.
RTUs and other automatic control devices were being developed prior to the arrival of industry-wide standards for interoperability. The result is that developers and management created a multitude of control protocols. Among the suppliers larger, there was also the incentive to create their own protocol to "freeze" its customer base. A list of automation protocols being compiled here.
Recently, OLE for Process Control (OPC) has become a widely accepted solution to communicate with different hardware and software, which allows communication between devices, whether or not originally intended to be part of an industrial network.
Tendencies SCADA
There is a tendency for PLC and HMI / SCADA software to be more "mix and match." In the mid-1990s, the typical DAQ I / O manufacturer supplied equipment that communicate using proprietary protocols on a suitable support route, such as RS-485. End users who have invested in a solution hardware of a particular provider were often restricted to a limited choice of equipment when needs change (for example, the expansion of system or performance improvement). To mitigate these problems, open communication protocols such as IEC870-5-101/104 and DNP 3.0 (serial and IP) became each increasingly popular among manufacturers and SCADA solution providers alike. Open SCADA system architecture allows users to mix and match different products suppliers to develop solutions that were better than those that could be achieved when restricted to the supply of products from a single supplier.
Towards the end 1990, the shift towards open communications continued with individual I / manufacturers Or, open structures that have adopted message as Modbus RTU and Modbus ASCII (originally developed by Modicon both) through RS-485. In 2000, the majority, I / O makers offered completely open interface as Modbus TCP over Ethernet and IP.
SCADA systems are coming in line with standard networking technologies. Ethernet and TCP / IP based are replacing older standards property. While certain features of technology-based communications network frames (determinism, synchronization, protocol selection, adequate environment) have limited the adoption of Ethernet into a few specialized applications, most of the markets have accepted Ethernet networks for HMI / SCADA.
"Next generation" protocols such as OPC-UA, SuiteLink Wonderware, GE Fanuc Proficy and Rockwell Automation FactoryTalk, take advantage of XML, web services and other modern web technologies, making them more easily bearable.
With the emergence of software as a service in the software industry wide, some suppliers have begun offering specific applications hosted SCADA systems in remote platforms via the Internet, for example, PumpView MultiTrode. This eliminates the need to install and commission systems in end-user facilities and take advantage of security features already available in Internet technology, VPN and SSL. Some concerns include safety, reliable Internet connection, and latency.
SCADA systems are increasingly ubiquitous. Customers lightweight, web portals and web-based products are gaining popularity among the major providers. The convenience of end users see their processes introduces considerations security remotely.
Security Issues
The move from proprietary technologies to more standardized solutions and open, with the increase in the number of connections between the SCADA and office networks and the Internet has become more vulnerable to attack. Consequently, security based SCADA systems has been questioned because they are increasingly seen as extremely vulnerable to cyber attacks cyber warfare /.
In particular, security researchers are concerned about:
the lack of concern for security and authentication in the design, implementation and operation of SCADA networks
the mistaken belief that SCADA systems have the benefit of security through obscurity use of specialized protocols and proprietary interfaces
the mistaken belief that SCADA networks are secure because they are supposedly protected physically
the mistaken belief that SCADA networks are secure because they are supposed to be disconnected from the Internet
Due to the nature of a large mission critical number of SCADA systems, such attacks could in a worst case scenario, cause huge financial losses due to data loss or physical destruction real, misuse or theft, even loss of life, either directly or indirectly. Whether such concerns will cause a departure from the use of systems SCADA for mission-critical applications to more secure architectures and configurations It remains to be seen, given that at least some influential people in business circles and government believe that the benefits and reduce the initial costs of SCADA based systems outweigh the costs and potential risks] Recently, several security vendors and Byres Security, Inc., Industrial Defender Inc., Check Point and nameless, and N-Dimension Solutions have begun to address these risks by developing lines of server industrial security specialist and VPN solutions for TCP / IP-based SCADA. The problem, said Eric Byres, CEO of Byres Security, is that "although many infrastructure organizations are doing a good job, others are lagging behind. When you have this diversity of effort, you are only as effective as its weakest link.
In addition, the security compliance ISA Institute (ISCI), begins to formalize the safety tests starting SCADA as soon as 2009. SICI is conceptually similar to private testing and certification carried out by vendors and 2007, as the Achilles Certification Program of Wurldtech Security Technologies, Inc. and the Mu Security MUSIC certification, Inc. Over time, standards are defined by ISA SP99 WG4 will supersede the efforts of initial sector consortia, but probably not before 2011.
About the Author
Yoda / Lamp / Anima Mundi / Central Station
|
98857 PC Acid Frost Apex-III Floor Lamp
PLC Lighting Modern 98857 PC Acid Frost Apex-III Modern Contemporary Floor Lamp CFL: Compact Fluorescent Lamp Included ORB: Oil Rubbed Bronze SN: Satin Nickel PC: Polished Chrome AL: Aluminum Since 1989, PLC Lighting, Inc. has continued to provide our customers with both contemporary and traditional lighting fixtures in a multitude of styles. Our product can be found in showrooms throughout North,…
|
|
08-09 Honda Odyssey OEM Style Clear Fog Lights + LED Bumper Lights
$104.99
Please Contact us For Any Questions You Have, All Your Email Will be Answer Within 24hrs (M-F) by Our 5 Star Customer Service Team.*********Guarantees Perfect Fitment. Good Quality.**********Fog lights provide greater visibility in rain, fog, and snow.**********Direct replacement, please check bumper openings. If you have aftermarket bumper, please double check if its the same shape….
|
|
Spyder Audi TT 00-06 LED Tail Lights – Black (Sold in Pairs)
$232.74
Tail lights are a necessity to anyone wanting to add that custom look to their car or truck. Tail lights are perfect for replacing any broken or faded factory tail lights, and give your car or truck an awesome new appearance. Tail lights are affordable, easy to install, and replace the entire tail light housing, however most maintain the factory bulbs and harnesses. Tail lights allow you to inexpe…
|
|
04-05 HONDA CIVIC 2/4D OEM STYLE YELLOW FOG LIGHTS+ DRL LED BUMPER LIGHT
$47.99
Please Contact us For Any Questions You Have, All Your Email Will be Answer Within 24hrs (M-F) by Our 5 Star Customer Service Team.*********Guarantees Perfect Fitment. Good Quality.**********Fog lights provide greater visibility in rain, fog, and snow.**********Direct replacement, please check bumper openings. If you have aftermarket bumper, please double check if its the same shape….
|
|
Mitsubishi XD250U XGA Projector
$1,499.00
The XD250U XGA projector features central control software, so you can monitor projectors, switch inputs, and broadcast messages to the classroom. Its a true communications aide within your education network. And all these innovative features are at your fingertips with new, simplified menu options….
|
