5. After the ice cream batch was complete, another autonomous controller would process the freezing of that ice cream. The company name stuck through a couple of acquisitions, then morphed into what is now Schneider Electric. PLC-Easy provides a lean-tested framework where functionality for every type of process and industry, as well as MES supporting functionality/data, can be easily created, added and modified by using basic programming skills. With the trend toward flexibility, many of the applications in the process industries share requirements traditionally thought to be exclusive to either DCS or PLC. Every day, thousands of new job vacancies are listed on the award-winning platform from the region's top employers. At Bedford, Morley and his friend wrote proposal after proposal, mostly for local tool firms hoping to evolve into the new solid state manufacturing arena with the help of small computers. With open source communications, fiber optics, Ethernet and the like, many PLCs can now communicate with each other and behave as autonomous PLCs that communicate over the network to other autonomous controllers. The advancement of the microprocessor resulted in a merging of the technologies. a DCS and a PLC were well defined. Today, we will dive into some of the advantages of PLCs. The idea of using a PLC-based system rather than a DCS has become a philosophical and technical debate in the industry. DCS was originally developed for analogue control. How to choose between PLC and DCS Systems ? The first name on the team sheet, your DCS is dependable, hardworking and controls the whole outfit. To receive our free weekly NewsBrief please enter your email address below: © Setform Limited 2019-2021 | Privacy policy | Archive. All upgrades are made online while the system runs continuously. Game on. Here again the DCS has an advantage over a PLC. The entire DCS database would be available for the creation of the monitoring and system, the PLC systems individual PLC databases would need to be created in the SCADA system software. Future of the DCS/PLC . The takeaway from this comparison is that, with today’s technologies, either system can control an entire plant. In essence, some industrial plants are now employing more than one captain to ensure critical systems are well managed. This advantage occurs because of the location of the autonomous controller to the process can be close in vicinity versus pulling long runs of I/O wire across a plant. Some uses of IPCs include OEM machines and skids and other small projects where space is limited. That interface may do something like handling the manual and automatic operation of a valve. For all their differences, PLC and DCS are becoming more alike. There are many advantages that a PLC system holds over a relay system. PLCs are designed to meet the needs of applications that require scan rates of ten milliseconds or less. They were initially developed to replace hardwired relays, sequences and timers used in the manufacturing process by the automation industry, but today they have scaled and are being used by all kind of manufacturing processes including robot based lines. Bottom line? One of the first and simplest advantages is reliability. A DCS typically covers an entire process, and is capable of covering an entire plant. In the early stages of design, the first priority is to define the project library of objects, such as valves. Based on the current rate of technological advancement, most experts agree it will be pointless to differentiate between DCSs, DDCs, and PLCs in the future. PLC VS DCS . You can reach her at: mondi.anderson@gmail.com, or email the RealPars team at: hello@realpars.com. This is because a DCS normally has built-in redundancy, ensuring a higher level of system insurance. Following are the benefits or advantages of SCADA: The system provide facility to store large amount of data. Yet another advantage of the DCS is installation cost savings. The big change in DCS over the past 20 years is its move from proprietary hardware to the personal computer (PC) and standard LAN technologies. It has great computational capabilities. Boom…GM heard about Morley’s work and eventually contracted with Modicon to purchase over $1 million worth of their innovative programmable controllers (it was several years later, when personal computers or PCs were invented and the “logic” part of the name was added to create the term, PLC). I hope all the above questions wont bother you much. By Mondi Anderson, Controls Engineer at Metawater USA and Automation Instructor at RealPars In a nutshell, a PLC or programmable logic controller is a ruggedized computer used for automating processes. There are some advantages of programmable logic controller (PLC) are given below, It has very faster scan time. As a utility player, PLCs are highly customisable. Function block programming saved a lot of time and redundant programming. With a modular or subsystem architecture, you can add new equipment to a DCS all day long. DCS took care of the delicate continuous processes like melting and conditioning control. Diagnostics in a PLC system will alert an engineer when something is broken. This advantage occurs because of the autonomous controller can be located in close proximity to the process versus pulling long runs of I/O wire across a plant. By Mondi Anderson, Controls Engineer at Metawater USA and Automation Instructor at RealPars. This kind of predictive analysis is particularly important for obsolete part replacement and avoiding costly downtime. There were many benefits to the DCS, but one of the primary advantages was that an entire plant could be connected via proprietary communications and controlled by a distributed system. The Benefits of DCS Using a DCS allows a plant’s engineering staff to supervise and manage a larger number of control loops and other similar plant components and processes. However, DCSs do not need to be this quick because they control systems rather than individual devices. It has capable to communication with computer in plant. A DCS today is just as functionally and cost-effective as a PLC in fast logic sequential tasks. Check out our free e-newsletters to read more great articles.. ©2020 Automation.com, a subsidiary of ISA, A subsidiary of the International Society of Automation. Your PLC is more like a utility player - he's nippy and doesn't mind where he plays, but don't expect him to be as reliable as your captain. In her lengthy career, Anderson has worked in a wide variety of industries, and with all of the top PLC systems, as well as the top names inHMI/SCADA. The speed of logic execution is another key differentiator between DCS and PLC. When the batch is complete, PLC-A communicates with PLC-B that the process was complete, and PLC-B then launches the freezing process. 2. After finding financial support, Morley’s new enterprise, Modicon, was created. For instance, say you had a plant that made an ice cream-filled cookie sandwich. A DCS combines one or more PLCs with an HMI, and allows the integrator to build both together. PLC-A could process the ice cream batch. It has shorter training time required. DCS designs often trade high levels of functionality for repeatability and dependability. Function block programming, if you aren’t familiar with it, is a section or several lines of code behind a single interface. 3.How can we say that PCS7 is a DCS ( as many customers stillhave some hesitation to accept PCS7 as DCS)??? The difference between distributed control systems (DCSs) and programmable logic controllers (PLCs) can be boiled down to a simple football metaphor. An entire DCS is much more expensive than a few PLC’s, but each have their advantages in any given situation and certain automated systems will always require one over the other. Do you know the Difference between DCS and PLC Systems ? Interestingly, this debate over the virtues of DCS vs. PLC has been ongoing since these two architectures came into existence 40 years ago. With a PLC system (multiple PLCs in a plant structure), you still need to create the supervisory and control system. Bayt.com is the leading job site in the Middle East and North Africa, connecting job seekers with employers looking to hire. Modicon was now in business, big time. A DCS will be able to take advantage of all the aspects of an automated system, from the machines and sensors to the controllers and computers. One of the drawbacks to the DCS has been the scarcity of programmers that have some experience with it. The reduced hardware and software requirements reduces cost. Redundancy. This is why DCS is now used in smaller applications, whereby it is not spread across the whole plant, but rather a complex subsection that needs reliable control. PLCs are designed to meet the needs of applications that require scan rates of ten milliseconds or less. Your DCS is your captain. A DCS or distributed control system is similar to a PLC in that it has rugged computer controllers, however, the DCS contains multiple autonomous controllers that are distributed throughout a system, also used for automating processes. 3. PLCs have a simpler architecture, as is evident from the diagrams above. ... DCS stands for Distributed Control System and PLC stands for Programmable Logic Controller. A DCS combines one or more PLCs with an HMI, and allows the integrator to build both together. crossed that line and put a PLC with HMI in charge of a con-tinuous process control application. A wide range of control application. Another major benefit of the DCS was the integrated monitoring and control system similar to today’s SCADA systems. One needs to weigh the system costs and the advantages/disadvantages to make the best decision for the situation at hand. For all their differences, PLC and DCS are becoming more alike. Yet another controller might process the cookie batch, while another might supervise the baking process. DCS is advanced version of PLC and DCS works in real time frame while PLC not. A PLC can become a “sub-system” of a DCS when the application calls f… In the beginning, the PLC was used primarily for discrete controls. A DCS's regulatory control loops generally scan in the 100 to 500 millisecond range. Lean more about: PLC vs Relay system. A DCS typically covers an entire process, and is capable of covering an entire plant. Basically, the creation of a DCS system came about because of the increasing use of microcomputers. A distributed control system (DCS) centralizes plant operations to provide flexibility and simplicity by allowing central control, monitoring and reporting of individual components and processes. 2. The best way to think about DCS and PLC is like this: in the majority of cases, a PLC controls a machine and a DCS controls a plant. As the price point of the DCS has come down, more manufacturers are looking at the advantages of DCSa architecture . S Bharadwaj Reddy May 1, 2019 January 30, 2020. In most small to medium size applications a single processor (though this is changing now too) has immediate access to all data and I/O and processes it as required. What's the main difference between DCS & PLC? The entire tag base is right there, already created for the process control, and available to use on the monitoring and control screens. Advantages of PLC over Relays: PLC increases the reliability, flexibility, and accuracy of the automation system. This saves in development time when programming a PLC. In those early days of automation, there was a clear spilt between DCS and PLC systems, with both types being designed for their specific tasks. DCS designs often trade high levels of functionality for repeatability and dependability. Mark Proctor is managing director of industrial spares supplier EU Automation. Fig. That’s when Morley began to think outside the box, literally. A DCS or distributed control system is similar to a PLC in that it has rugged computer controllers, however, the DCS contains multiple autonomous controllers that are distributed throughout a system, also used for automating processes. The plant would have a production line for the ice cream, and one of the autonomous controllers would process the batch of ice cream. This allows them to accurately control motors and drives running at high speeds. The data can be displayed in various formats as per user requirements. Here we are comparing PLC with the relays and DCS (Distributed Control System). This is another myth. 4.If point 3 is convinced what are the advantage of PCS7 over other DCS like Honeywell ,Yokogawa etc.????? Conversely, PLCs are often used when the value of the product is relatively low and production needs to be flexible. A few thousand I/O points can be handled by a PLC whereas DCS can handle many thousands of I/O points and accommodate new equipment, process enhancements, and data integration. Benefits or advantages of SCADA. As good fortune would have it, during the design phase of Morley’s creation, an executive at GM presented a request for a solid state controller that would make plants more reliable and durable, one that could also replace the hardwired and unreliable relay systems that were pervasive in manufacturing. Important Issues . Demonstrating advantages ABB was able to offer CEE some examples to demonstrate how savings can be realised by using today’s DCS workflow, when compared with a PLC/HMI (SCADA) system. Select the right control system . 1. The PLC was actually born more than forty years ago when an antsy design engineer named Dick Morley quit his job over a dispute with his boss (he wanted to work on Saturdays instead of Fridays, so he could ski more…his boss said no) and formed a company with a friend called Bedford Associates. A DCS is used when the value of the products manufactured is high, the production is continuous and failures in the system result in damage to process equipment - for example, if a glass kiln dropped below a certain temperature. This is all about the Programmable Logic Controller aka PLC. These days, there is probably no single factory in the word that … In addition, today's DCS hardware is not as expensive as it was a couple of decades ago and is less difficult to implement. 2 (original print article) gives a Venn-diagrammatic picture of the situation, which is still changing as PLC and DCS vendors adapt to "soft" PLC technology and "smart" bus-connected field devices. This is why DCS is now used in smaller applications, whereby it is not spread across the whole plant, but rather a complex subsection that needs reliable control. It is also no longer as cumbersome either - modern DCS hardware resembles a PLC in size. There is no monitoring devices in PLC like DCS. Mark Proctor is managing director of industrial spares supplier, FREE Subscription to Engineering magazines. With several autonomous controllers, if a controller failed, it would impact only that process and not all of the others, which led to a robust system that virtually eliminated entire plant failure. Because of the specialized training, DCS programmers are a bit harder to come by. This change has brought about a certain level of technological convergence between PLCs and DCSs that defies traditional ideas of the two. When designing a logic diagram using PLC or programming logic devices it has many advantages over the traditional wired logic some of the advantages besides a fast response time: 1- complex logic can be achieved using the same PLC unit. DCS was originally developed for analogue control. Morley got to work drafting an idea for a programmable controller. Tag: advantages of dcs over plc. You can slap in as many controllers and networks as you can afford. In this article, I tried to cover all the PLC basics required. One advantage of IPCs is that it is often possible to run the HMI application on the same machine as the automation program and decrease cost. Whereas in a DCS, asset management software provides alerts of what might break before it does, so a fitting substitution can be made. PLC (especially Compact PLC) has a lower cost associated with it as compared to the other automation technology. DCS vs. PLC DCS stands for Distributed Control System. Another advantage is the onboard monitoring and control system. So if you have a large facility with parts of your process strewn throughout, then a DCS will assist you better. The speed of logic execution is another key differentiator between DCS and PLC. Mondi Anderson works as a Controls Engineer at Metawater USA, a global company focused on water treatment technologies, equipment and engineering. For example, take the server halls of data centres: these types of control systems are often seen as hybrids of both DCS and PLC. Benefits of DCS for Hybrid Industries versus Conventional PLC Approach: Your questions answered Webcast presenters Jerry Espy, Frank Prendergast, and Jerry Bartlemay answered questions about topics such as cybersecurity risk, the emergency of the … You can see that with today’s technologies, a wide and robust PLC system could do virtually the same thing that the DCS can do. The DCS may still offer some advantages when it comes to redundancy and hot swap capability, but new PLCs can offer that today, too.” Dolan considers the PLC to be a less expensive solution to a given application than DCS. In an earlier article, I have explained the top 25 advantages and disadvantages of PLC over the relay system. On the other hand, engineers expect a DCS to offer an out-of-the-box control system with features such as - historian, sophisticated alarms and logic from pre-existing function blocks. It is also no longer as cumbersome either - modern DCS hardware resembles a PLC in size. The DCS’ onboard monitoring and control system is also a plus. On the other hand, PLCs evolved from solid state relays and, as opposed to DCS, were used where process restarts were not a major concern, but processing speed was important. DCS can be preferred when advanced process control is required and contain a large facility that’s spread out over a wide geographic area with thousands of I/O points. “The ability to employ a single, hybrid control strategy that combines the benefits of both DCS and PLC/HMI control is a huge advantage for a company today, enabling them to run completely different processes from the same controller environment,” Ryan said. 3. Abig differentiator of DCS over PLC/SCADAis the standardisation they provide. For example, take the server halls of data centres: these types of control systems are often seen as hybrids of both DCS and PLC. There is no clear cut fast rule about when to use a PAC, PLC, or IPC. PLC Pros: 1. This makes it easier to implement and maintain. In a nutshell, a PLC or programmable logic controller is a ruggedized computer used for automating processes. Like a good captain, the highest priority of a DCS is to deliver reliability and availability. Take the ice cream sandwich example. 4. It was over 35 years ago that the first DCS systems were installed in glass industry processes. He wondered if he could create an automated programmable controller that could handle his clients’ everyday jobs. In her free time, Anderson is a RealPars video instructor. What are the Advantages and Disadvantages of PLC? Most plant floor technicians are familiar with ladder logic programming however, DCS programmers and technicians typically need more specialized experience in database functions, as well as IT-related networking knowledge. It provides interface to connect thousands of sensors across wide region for various monitoring and controlling operations. The programming of the PLCs was primarily in ladder logic, a format very similar to a schematic. DCS stands for Distributed Control System. There had been other computer-based systems in the industry since the late 1950s, but these had limited scopes for scalability, robustness, and security. Speaking of advantages, today’s PLC systems offer nearly the same ones as the DCS, excluding the supervisory control and data acquisition (SCADA). In addition, today's DCS hardware is not as expensive as it was a couple of decades ago and is less difficult to implement. Systems can be shut down for maintenance, troubleshooting or upgrades without damage to equipment or significant downtime costs. However, consumers willing to adopt automated robotics applications in their manufacturing processes still need to understand their differences. The DCS was really good at autonomously controlling single or multiple processes. In today’s industries, however, the DCS and PLC are quite similar, save for the integrated monitoring and control. Figure 2. An advantage of the DCS is installation costs. The DCS appeared around 1975, out of necessity. The benefits of a DCS are combined with the benefits of a PLC, without the disadvantages of both systems. Traditionally, a DCS system was expensive, large, complex to implement and only seen as a control solution for continuous or complex batch process industries. He shared it with his team who enthusiastically embraced the design. Reliability. However, the latest generations of PLCs are increasingly capable of delivering simple to complex proportional integral derivative (PID) control. About Bayt.com. They have standard libraries and routines built in, but also have the capability to be specially programmed using custom code from scratch. The PLC received device information from the field, solved the logic, and then energized the outputs to produce the desired effect, which generally meant performing repetitive tasks in a reliable and durable manner. Learn about some of the advantages that PLC systems have over a relay system. A connected PLC system can have nearly the same security and robustness as a DCS, while a single PLC is a single point of failure, so you wouldn’t want to control an entire plant with a single PLC. That wide communication allows for single or multiple processes being controlled by one PLC to communicate with another PLC. Response times of one-tenth of a second make the PLC an ideal controller for near real-time actions such as a safety shutdown or firing control. In contrast, there are more programmers available for hire in the PLC arena and with the new programming languages such as function block, sequential function, etc., the advantage of function block programming is no longer exclusive to the DCS. Also beneficial was that the DCS had function block programming. The PLC is cost effective from 0 to a few thousand I/O points. DCSs have been the primary solution for process automation but now many PLC vendors are arguing that a single integrated architecture based on PLCs and/or PACs is the best approach to total plant automation. However, the latest generations of PLCs are increasingly capable of delivering simple to complex proportional integral derivative (PID) control. A DCS takes much longer to process data, … The proposals didn’t exactly meet Morley’s creative nature—they were so similar and repetitive that, being the antsy type, he eventually grew bored. A Programmable logic controller(PLC) is simply a special purpose computing device designed for use in industrial control systems and other systems where the reliability of the system is high. Modern industrial applications are demanding the reliability of a DCS system but the flexibility of a PLC. Controlling single or multiple processes being controlled by one PLC to communicate with PLC... 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