http://www.controleng.com/ en http://www.controleng.com/typo3conf/ext/tt_news/ext_icon.gif http://www.controleng.com/ 18 16 TYPO3 - get.content.right http://blogs.law.harvard.edu/tech/rss Tue, 21 May 2013 07:00:00 -0400 http://www.controleng.com/industry-news/single-article/hacked-without-knowing-it/e5d9c2b312d10880e3c64a3745751d9a.html Engineering and IT Insight: Cyber-criminals are stealing manufacturing companies’ intellectual... It is hard not to be afraid, maybe very afraid. Recent news articles and security analyst reports have listed the types of attacks and illicit information gathering directed against manufacturing companies, and they are not what you may expect. Much of the current press announcements are about stealing credit card information, social media account passwords, and social security numbers, but cyber-criminals are after something much more valuable in manufacturing companies—their intellectual property (IP). While national security agencies are pushing companies to harden critical infrastructure against disruptions from cyber terrorists, there is less attention given to protecting the intellectual property that manufacturing companies have spent millions of dollars to develop. Advanced persistent threat Companies compromised by directed attacks, usually called advanced persistent threats (APTs), have included those in the aerospace, energy, transportation, pharmaceutical, biotechnology, engineering services, high-tech electronics, chemicals, food and agriculture, and metals industries. Information stolen has included product development data, test results, system designs, product manuals, parts lists, simulation technologies, manufacturing procedures, descriptions of proprietary processes, standard operating procedures, and waste management processes. This is information that can be used to replicate production facilities. Many companies think this information has little value outside their company, but if they have global competition and the competition can replicate products and processes at a fraction of the cost, there will be damages. Most of your competitors will not resort to using illicitly acquired information, but if your competition is based in a country with limited intellectual property rights, or even in a country actively stealing manufacturing IP, then you are at risk. If you are at risk, you may have already been hacked and not even know it. Intellectual property theft is done in a stealth mode. There is a saying among cyber security experts that there are only two types of companies: those that have been hacked, and those that don’t yet know they have been hacked. Once an APT has established access, the thief will periodically revisit the victim’s network over several months or years and steal technology blueprints, proprietary manufacturing processes, recipes, SOPs, and test results. APTs have been known to maintain access for several years and steal gigabytes of data before they were eventually detected. If you don’t want an unscrupulous competitor to use your SOPs, production processes, product definitions, and recipes, then it is up to you to ensure that your IT department is protecting your manufacturing IP. The IT department is probably already protecting its financial and personnel records, but it may not realize the value of your manufacturing IP. With physical security, a company can reduce your risk by operating in safe neighborhoods, alarming all of your windows and doors, and hiring security guards. Unfortunately, with cyber security there are no safe neighborhoods. The Internet has put cyber-criminals only one click away from your doorstep, so we are all in the same electronic neighborhood. There is no equivalent for the neighborhood beat cop who looks for suspicious behavior and checks that doors and windows are closed and locked. In the electronic neighborhood you have to protect yourself. This means that companies need to install firewalls for protection to the outside, and firewalls and account protections within the corporate network. Interior firewalls provide the same level of protection as locked interior doors and filing cabinets inside locked buildings. You don’t want to make a cyber-criminals’ jobs easier by giving them unrestricted access once they are inside the corporate network. Don’t believe that a single firewall will protect all of the internal systems; install firewalls and security access between business systems and manufacturing systems. Access points With physical security, windows and doors are the ways in and out. With cyber security, the ways in and out can be different. Many attacks are introduced through infected USB drives and email, but report back through Internet communications. IT departments should have procedures in place to monitor all outbound Internet traffic for suspicious and atypical behavior. For example, there may be a burst of communications to overseas servers from a manufacturing server at the same time every day, or a set of port scans coming from a server that should be running only document management services. These are indications of a compromised system. Maybe you cannot always keep the bad guys out, but you can recognize when you have been hacked and you can keep them from phoning home. With physical security, companies can employ security services to monitor alarms and provide guards to look for suspicious activity. If your manufacturing IP has value and would put you at a corporate disadvantage if stolen, then you need to employ active measures to maintain security. These can be accomplished through port scans, checks of actual installed vs. approved programs and libraries, checks of actual vs. approved accounts, and checks of actual vs. approved scheduled tasks. These checks need to be scheduled so they don’t disrupt production systems. Fortunately, someone stealing intellectual property does not want you to shut down production. The thief wants to get your information without you knowing, so many thefts are not from production systems but from the secondary support system, such as document servers, design systems, and backup systems. This means the IT department can usually be very aggressive in checking support systems without impacting production systems. Making your own safe neighborhood, locking and protecting your assets, and employing active measures to check for security breaches are the main tools for protecting your manufacturing intellectual property. There are bad guys out there, and they want to break in. You should work with your IT department to make sure you can keep the bad guys away from your manufacturing IP. - Dennis Brandl is president of BR&L Consulting in Cary, N.C., www.brlconsulting.com. His firm focuses on manufacturing IT. Contact him at dbrandl@brlconsulting.com. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering and Plant Engineering, mhoske@cfemedia.com. ONLINE extra This posted version contains more information than the print / digital edition issue of Control Engineering. At www.controleng.com, search cyber security for more on related topics. See other articles for 2013 at www.controleng.com/archive. See other security and safety articles. ]]> System Integration Information Control Manufacturing IT Tutorials Plant Safety and Security Slider Homepage Item - CTL June SyndicationType: Article SyndicationSource: CFE Media (in-house) SyndicationSource: Freelance/contracted Tue, 21 May 2013 07:00:00 -0400 http://www.controleng.com/industry-news/single-article/should-you-be-an-early-adopter-of-microsoft-server-2012-for-todays-control-systems/b9cd9c05421930525ef06c1e27b62810.html You might get ahead of your control system software suppliers, but you can probably install the...
After further research, I could find no reason not to leverage Server 2012 on the new primary domain controller. I checked with the primary control vendor supporting this particular customer, and they saw no reason not to use Server 2012 on the primary domain controller. I went a step further and checked with colleagues on their experiences with the differences between Server 2008 R2 and Server 2012. Since there were no issues identified, I recommended the customer move forward with purchasing and installing this new platform as the primary domain controller for their plant control system. The customer ordered the new server hardware and their IT department purchased their first volume license of Server 2012 standard.

The experience of installing Server 2012 was very similar, if not the same as installing Windows 8 Professional. At the end of the installation, I was surprised to see the start button had disappeared as it had with Windows 8 Professional. With Server 2012, all of the applications are the desktop type, all neatly organized on the start screen based on which roles you assigned to the server (see graphic). On previous versions of Microsoft Server these were inadvertently buried in other submenus and took some digging to find. This seems to be much more intuitive to use then the start screen that Windows 8 Professional has. I would also like to note that promoting the server to a domain controller was much more automated than previous Server versions, and it added the supporting roles necessary for the domain controller to function properly. Any additional help that I needed was easily found at Microsoft’s support site, or by simply doing an internet search. The other new feature that I found was the new Server Manager’s Dashboard. This makes it very easy to monitor any status and / or issues with any of the roles the server, or servers within a group are providing (see graphic). During the deployment, the new domain controller computers throughout the plant were joined to the domain with no problems. The plant control system computers contained the following operating systems: Windows XP Professional, Windows 7 Professional, and Server 2008 R2.

This experience should highlight the fact that even though many of our prominent control vendors do not support the latest operating systems that Microsoft releases, this does not mean that supporting systems cannot use the latest Windows operating system available in supporting roles. This not only provides added value for the customer, but also allows us to become proficient on the latest software available. You too can be classified as an early adopter, even if you are working with legacy control software.

This post was written by John Boyd. John is a technology leader at MAVERICK Technologies, a leading system integrator providing industrial automation, operational support, and control systems engineering services in the manufacturing and process industries. MAVERICK delivers expertise and consulting in a wide variety of areas including industrial automation controls, distributed control systems, manufacturing execution systems, operational strategy, and business process optimization. The company provides a full range of automation and controls services – ranging from PID controller tuning and HMI programming to serving as a main automation contractor. Additionally MAVERICK offers industrial and technical staffing services, placing on-site automation, instrumentation and controls engineers.]]> Manufacturing IT Information Control Slider Homepage Item - CTL Real World Engineering SyndicationType: Article SyndicationSource: Systems Integrator/consultant SyndicationSource: Content Partner - Maverick Technologies Syndication: System Integration System Integrators Syndication: Information Systems Software (Asset Management Alarm Management CMMS MES SCM ERP Production Scheduling CAD T&A OM) Mon, 20 May 2013 12:10:00 -0400 http://www.controleng.com/industry-news/single-article/machine-safety-does-iso-13849-1-2006-weight-severity-frequency-and-probability-equally/e9d59ef42f3466256cba0d5cb324c41d.html New quantitative requirements for designing safety-related parts of the control system (SRP/CS)... Ten years later in 2006 ISO 13849-1 was updated and released introducing Performance Levels and the requirement to develop the PLr, which I call the goal. To develop the PLr, we again use the qualitative approach by evaluating the related potential injury by severity, frequency, and probability also shown in the graph. There’s a whole lot more we could get into here but let’s keep it focused at the three questions. What was the criteria for approaching these three questions in their order of severity, frequency and probability? Is severity weighted the most because it’s the first question? Such as; S = 50%, F = 30% and P = 20%? Or is probability asked last because of its greater impact? Such as; S = 25%, F = 35% and P = 40%? Or, does it matter at all? Can all three questions be equally interchanged? Can anybody provide some insight and background? Has this presented you with any new perspectives? Add your comments or thoughts to the discussion by submitting your ideas, experiences, and challenges in the comments section below. Related articles: Machine safety: Confusion amuck, quantitative circuit design versus qualitative risk assessment. Machine Safety: Can end user companies comply with ISO 13849-1: 2006 without design engineering resources? Machine Safety – incorporating “Functional Safety” as part of your machine safety plan – Part 1 Contact: http://www.jbtitus.com for “Solutions for Machine Safety”.]]> Machine Control Plant Safety and Security Tutorials Machine Safety SyndicationType: Article SyndicationSource: Freelance/contracted ArchivedSyndication: Safety Security (Intrinsic Process Machine Plant Arc Flash OSHA Personal Protective Equipment) Syndication: Codes Standards Regulations Slider Homepage Item - CTL jb@jbtitus.com Mon, 20 May 2013 07:00:00 -0400 http://www.controleng.com/industry-news/single-article/the-industrial-internet-of-things/c98837a0efec387df9fc14c2de0a3b2f.html Should industrial users embrace IP networking? It promises convergence of many technologies, but is... Editor’s note: While the concepts related to the Internet of Things are much in the news for consumer applications and products, does this technology belong in the industrial space? Herman Storey sees potential for major benefits, but only if the technology is applied correctly. Storey is co-chair of ISA100 and has been involved in many networking standards groups throughout his career. He offers these thoughts as a starting point for an ongoing dialog. His comments are followed by views from two others. Concepts referred to as the Internet of Things (IoT) and machine to machine (M2M) communications have attracted a lot of publicity, many interest groups, and many face-to-face meetings. IoT refers to the increasing connectivity of objects of all kinds, from home appliances to devices used in industrial applications, either to the Internet or some kind of Internet-like structure. The general idea behind this effort is that any smart devices should be able to communicate with each other or with human interfaces anywhere on the planet—thus driving improvements in productivity. Industrial M2M networks are mature and widely deployed, even though some M2M publicity implies that the concept is new. These industrial networks can benefit from IoT technology if done correctly, but could also suffer if done with a lack of planning and caution. This discussion will propose some general principles for applying IoT to industrial automation systems. To differentiate this from the web-based efforts and call attention to industrial needs, this will be called the Industrial Internet of Things (I²oT). I²oT must give priority to security, robustness, and timeliness requirements of automation networks while providing for remote access as a secondary requirement. Why and why not For the world of automation, I²oT represents the opportunity for partial convergence of industrial automation communication on a grand scale. It will allow improvements in functionality, security, flexibility, ease of use, and cost savings. In the long run, it will be good for vendors and users. It will be good for the whole automation industry, and all who embrace the technology will benefit. In the short run, this is disruptive technology. It will require changes and will threaten entities that do not have the resources or leadership to make the changes. It will cross organizational lines and blur distinctions between foundations. The challenges of realizing the benefits of this technology will be more organizational in nature than technical. In fact, the technical challenges are minor by comparison. As of now, the effort to incorporate I²oT technology into the world of industrial automation does not have a home or a clear statement of reason for being. This is not for the faint of heart or the impatient. What is it? The intent of this discussion is to provide a model for I²oT. It is oversimplified but should form the basis for more discussion and definition. This is not a proposal for a massive amount of research into new communication technology. It is a plea to use what we already have in a rational manner. A lot of assembly is required and some gaps need to be filled. Essential elements—I²oT will provide a means to integrate multiple physical media and multiple applications into a single system of industrial networks utilizing some common technology. I²oT is not a converged single stack with a single application layer or a single physical media. Indeed, one physical medium will not serve all installation requirements, and we need more than one application layer to serve all use cases. This discussion may miss some elements but should serve to stimulate discussion to fill in the gaps. The major elements are shown in the following illustration and discussed below. Applications—At the top of the communication stack, we have many application layers (and some user layers that may or may not be a part of the application layer depending on philosophical prejudice). It can easily be argued that we have many more application layers than necessary, but the argument is irrelevant because they now exist and constitute a large installed base. It is also arguable that one new application layer will not displace all of the existing application layers. Each application layer has strengths and weaknesses that allow each one to fill a market niche. It is simpler and more reasonable to assume that multiple interfaces are necessary and that we should expect to support all of them when considering the future of industrial communications technology. IPv6—If I²oT supports all existing media and application layers (and it should), what is converged by I²oT? The answer is simple: in the world of I²oT, all protocols would use Internet Protocol version 6 (IPv6) as the network layer of the communication stack. IPv6 has an extension called 6LoWPAN that will allow this network layer to be used on low power and/or bandwidth-limited networks. It was originally designed for use with battery-powered radio networks, but is suitable for wired networks as well. IPv6 with 6LoWPAN literally gives a protocol the ability to address and route messages to and from any device on the planet to any other device on the planet. Any media should be able to support IP, and any application should be able to run on top of IP, and many already do. Use of a common and capable network layer will allow the first phase of convergence including the sharing of media by multiple applications and the selection of the optimum media and application for any particular task without the need for separate infrastructure. Physical media include:

• Single and multiple twisted-pair wires
• Coax cable
• Single- and multi-mode fiber
• Many types of radio
• Acoustic, and
• Infrared.

PHY/MAC specifications exist for these media types and do not need reinvention. All of these types of media should continue to be supported. However, many of these physical- and link-layer specifications are now tied to a single application layer by many protocols. This linkage needs to be broken, and it can be broken quite easily. Furthermore, the linkage should be broken in a way that any media can be shared by multiple applications. Installations that have high latency and low bandwidth because of physical limitations (such as distance) will require some differences in the layers above IP as well as possibly placing limitations on the media that can be used. There are some shortcuts and simplifications that can be made when networks have direct high-speed/low latency links. A communication stack model that has multiple options at the top and multiple options at the bottom but a single network layer is sometimes called an hourglass model, or a Hedy Lamarr model for history buffs who remember she invented and patented direct sequence spread spectrum technology during World War II. Switching and routing—Switched networks are the technology of choice. Protocols that do not support switching and routing need to be upgraded, and the common network layer will aid in that step. Point-to-point and multi-drop busses will need gateways to communicate in the new world, but new networks should simply be able to connect to a switch or router. In this model, switches or routers can accomplish media conversion without a gateway. With the right switching and routing technology, it may be possible to incorporate IPv4 as an additional option for the network layer. It is worth investigating. Common sense of time—A common sense of time is necessary in real-time networks for event tagging, scheduling of communications and applications, and security. The best time to use is GMT or TAI (which can be converted to local time for human interface). A simple time counter or local time will lead to problems in system implementation and maintenance, and could degrade security. Some protocols need an upgrade. Unfortunately, time synchronization is not so easily standardized because of differing needs of networks and applications. Where time synchronization requirements are fairly lax, SNTP can be used. Many networks and some applications require synchronization at the millisecond level, and a variety of methods are used for this purpose. This is an area of standards development. Tokens should not be used for scheduling. A proper clock in each device will eliminate the need and allow more efficient and robust scheduling mechanisms. Tokens may be used for some non-scheduled bus control (TCP), but in general tokens and industrial communications should not go together. More networks will require an upgrade. Architecture—ISA100.15 has published a document that gives models and terminology for architectures suitable for I²oT. It does not spell out in detail how elements of the architecture should be implemented; it just identifies and gives examples of what they do. More detail is needed if some degree of interoperability is to be achieved with I²oT. Architectural principles of I²oT:

• ISA100.15 illustrates methods for segregating automation networks in zones and connecting the zones with conduits. The concepts for zones and conduits were developed by ISA99 for ISA/IEC 62443.
• ISA100.15 illustrates methods for creating and enforcing policies that determine which entities can communicate over industrial networks, and the allocation of bandwidth or relative priority of those communications.
• As a general principle, many automation nodes and networks have limited bandwidth and capability to serve data. The primary source of data from these nodes must be in separate buffers and caches with sufficient bandwidth for expected users. Direct access to nodes requires systematic limitation.
• Local autonomous control and local history collection and compression are two techniques that are used in industrial automation systems to deal with low bandwidth and/or high or variable latency in networks. Many proprietary schemes are used to fill these needs, and there is an opportunity to standardize these features.

Common network management—ISA100.20 is starting work on a recognized need for common network management. This is a gap that needs to be filled. Common network management is intended to provide a way of managing multiple diverse networks with common tools. Some of the tools already exist, but many networks are not designed to work with external tools. Some networks are unmanaged. This is an opportunity. Common security management—This aspect will also need work. It is not easy to separate this need from common network management, and it may be handled by the same effort. This will need to include provisioning procedures and tools. Most industrial protocols do not include sufficient security. They need to be upgraded to include this as a standard feature. Specifications and profiles to support compliance certification—We need plug and play, not plug and pray. This means that we will need enough compliance profiles and specifications that a certification body can do compliance testing. Standards developed by a standards development organization may support this cause, but will not be sufficient to meet industry needs. What does the future hold? There are multiple paths and even multiple end points for this technology migration. It is not certain what path(s) or endpoint(s) will be the final result. The only certainty is that this technology will change, and so far the changes have led to more diversity. Current state—Many organizations are involved in pieces of the communication problem, but no single organization is involved in all aspects of this problem and no organization is well positioned to take the lead in coordinating this technology drift. Some standards organizations have taken on the task of standardizing horizontal layers of the communication stack. IEE writes standards for the PHY/MAC (or link) layers. IETF writes standards for network and transport layers. Coordination at the boundary between the link and network layers (which is also an organizational boundary) is informal at best and sometimes appears to be a turf war. Many foundations have taken a vertical approach to communication stack specifications and have written full top-to-bottom stacks. Many of these support only one PHY and one application and have a single stack in between. Others have multiple PHY layers available but with restricted stacks in between. These foundations are generally market competitors. All of the organizations fill a need whether they are working on a horizontal or vertical slice of the communication problem, or just a little piece of the problem. All of these organizations could slowly converge on best-in-class technology, or not. If market forces do eventually drive this convergence, it is safe to assume that the convergence will happen very slowly and chaotically under market conditions. Lead organization—Building a positive outcome will need a lead organization or a consortium of organizations to make this effort successful. It will involve liaison work with too many organizations to name, and will need executive sponsorship from multiple entities including vendors, standards organizations, and foundations. Herman Storey is chief technology officer of Herman Storey Consulting, LLC. See additional voices on the topic on the next two pages: The technology solutions we create must be easy, flexible, and powerful Rick Bullotta Any consideration of applying the concepts from the IoT to the industrial space would be incomplete without addressing the following:

• Legacy systems and devices—How will they participate in this new architecture, at all levels of the stack? While IPv6 and 6LoWPAN are important moving forward, we need to embrace existing devices and endpoints as well.
• The IoT and I²oT are not a communications/plumbing problem (or opportunity); they are about creation of useful applications. While standardizing some of the lower level networking is helpful, it will fall far short of truly unlocking the potential and represents only a tiny piece of the requirements. Other critical elements include:

1. A semantic model for discovering, addressing, and consuming the data, services, and events that the elements of the IoT/I2oT will provide. Although the “I” in the IoT stands for Internet, the reality is that the Internet wasn’t necessarily the source of the amazing innovations we’ve seen that have changed our lives. It was in many cases the WWW and related standards and protocols that ran on top of the Internet. The same will be true of the IoT. 2. Highly granular security models that can protect access to very specific device capabilities. This way, we can allow selective sharing and access control, better deal with cyber security implications, and so on. 3. Quality of service (QoS) and security at the network layer. Not all messages and bits that are passed on the IoT and I²oT are of equal importance, and this needs to be designed into the stack. IPV6 offers some capabilities in these areas, but more is required. Let’s not forget the human side of the discussion. People still represent the sensors, actuators, and knowledge base for a huge amount of industrial processes. Failure to consider how humans will interact in the I²oT will lead to failure! Despite some vendors’ claims to the contrary, the IoT and I²oT are not simply cloud device architectures. In fact, to be successful, secure, reliable, and capable of performing as required, we need to consider them as a distributed systems architecture. Those of us who come from the industrial automation world have been dealing with these types of problems for decades, and there is much to be learned from past experiences and applied to the IoT and the I²oT. Standards are important, but we need to consider carefully where in the stack to focus our energies first on standardization. For example:

• Which areas have the most immediate impact/value?
• How can we address the issue of legacy integration?
• How can we “future proof” our standardization efforts so that when IPv24 and infinitely fast, zero gravity, powerless wireless communications are available, we aren’t starting from scratch?
• Consider not only the use cases of the past, but the use cases of the future.

Moreover, how can we embrace some other key elements of the IoT in the I²oT?

• Location awareness of assets, people, and even data. Data has time, value, quality, and location.
• Contextualization of data via metatagging and other mechanisms, such as a move from dumb historians to smart historians,
• Mobile devices and new modalities for interaction, including push-based notifications, search-based access to information, secure connections from anywhere, and so on, and,
• Extend the concept of the social graph to the equipment, processes, systems, and people in the work environment.

We at ThingWorx are using our extensive experience in the industrial sector (the founders of ThingWorx brought experience from Wonderware, Lighthammer, and Cimnet) to apply those lessons and know-how to the IoT and the I²oT. We share the view that there is huge value to be unlocked. We also passionately believe that the value will be unlocked when we provide technology solutions that are easy, flexible, and powerful. Those elements need not be mutually exclusive. And security and reliability are a given. We also feel strongly that there is much to be gained from sharing experiences and technology in both directions—applying the lessons learned from the open, mobile collaborative, and composable world of the IoT to the industrial space, and leveraging decades of knowledge and experience in delivering reliable, performance driven, distributed systems that exist in the industrial sector. Rick Bullotta is CTO and co-founder of ThingWorx.  Don’t miss the big space in the middle  Daniel Drolet Over the past 25 years, there are two ends to the spectrum of thought related to this process in which the world needs to be viewed in order to properly launch both the IoT in general as well as the I²oT. Industrial automation and control always needed to be mechanized through machines—such as manufacturing, processing, buildings, energy, transportation, etc.—and over time and through that evolution we began adding efficiencies and minimizing labor. We then progressed to distributed control, which led to distributed sensing, which then led to distributed intelligence for critical systems. Meanwhile, on other end of spectrum—the consumer or human interface end—this group embraced all of the devices that were being produced from the factory (which were themselves utilizing automation equipment) whereby humans became interested, intrigued, and overly addicted to the great conveniences, comforts, and improvements to their overall quality of life. This ultimately caused two interesting results; where one extreme improved the mechanism of production (i.e., industrial and factory floor), the other caused the benefits and value to be realized by human users which ultimately developed the residential and consumer markets. As we all know, the consumer markets that developed for radios, televisions, and appliances led to the convenience of cell phones, tablet computers, smart devices, consumer GPS, and other intelligent devices that improve our day-to-day lives. This created one very important and often overlooked realization—recognition of the two extremes often misses the continuum between the two extremes, and what that continuum represents—such as the entire commercial industry of services, products, point of sale, payment systems, security, and overall societal infrastructure that we use every day in our life and work. This entire continuum IS the IoT which involves distributed control, distributed sensing, distributed intelligence, M2M communications, and human interface and interaction such as social media, which is driven from an underlying theme and infrastructure of e-commerce. This essentially relates to all activities that are important to a human or other entity. What Herman Storey describes is the two ends of the spectrum. PCN believes that focusing on the interconnectivity of the two ends by enabling intelligent infrastructure for the continuum in the middle is required to have a successful IoT or I²oT. PCN has developed technology and products to enable rapid upgrade to “intelligent infrastructure” through repurposing and reusing existing legacy infrastructure. I²oT deployments can then be realized with linkage specific to the overriding goals and objectives of what I²oT is supposed to be, and allows the “industrial communication revolution” to finally take hold. Due to cost, timelines, operational shutdown, security, and capital expense requirements alone, society cannot simply shut down to replace legacy infrastructure with new IP based communication infrastructure in order to achieve its overall goals with IoT or I²oT. There are new technologies on the horizon and bleeding ones here today that are the stepping stones for deployment of multiple architectures on single communication or existing communication infrastructures. By being able to use existing functioning infrastructure as is, and while simultaneously overlaying IP Ethernet networks anywhere within that infrastructure, network owners easily deploy new devices, applications, and systems without impacting those that are currently performing a required task. Managed migrations to the “industrial Internet” and I²oT can now be a global successful effort that ensures critical infrastructure upgrades within industrial systems, buildings, energy, oil and gas, transportation, and other industries. Daniel Drolet is executive vice president of PCN Technology Inc.  Key concepts:

• Internet protocol technologies are quickly moving to industrial applications.
• The Internet of Things offers many potential benefits for industrial users, but only in the right contexts.
• A careful and purposeful approach can make adoption more practical and avoid many pitfalls.

For more information, visit: www.isa.org
www.pcntechnology.com
www.thingworx.com
]]> Process Control Manufacturing IT May SyndicationType: Article SyndicationSource: CFE Media (in-house) Syndication: Manufacturing Methods (Quality Six Sigma Kaizen Kanban Lean Manufacturing Project Management) Syndication: Control Methods (PID Advanced Process Control) ArchivedSyndication: Industrial Networking (Wireless Ethernet Sensor Networks Fieldbus IoT) Syndication: Codes Standards Regulations Syndication: Information Systems Software (Asset Management Alarm Management CMMS MES SCM ERP Production Scheduling CAD T&A OM) Wed, 15 May 2013 14:34:00 -0400 http://www.controleng.com/industry-news/single-article/understanding-sis-industry-standards/90db923905bf9f60271f67a82ad3592c.html Process safety standards and practices are spreading from oil and gas and other energy-related... An SIS provides an integrated approach to complete safety loops, as shown in Figure 1. Such a loop includes a sensor, logic solver, and final control element. The SIS system shuts down a process plant or part of a plant when needed for safety, but keeps the plant running safely when devices fail. What is a safety function? Safety instrumented functions (SIFs) are actions taken by a SIS to shut down the process plant safely. Each identified SIF consists of a set of actions to protect against a specific hazard. A process plant SIS therefore consists of a number of SIFs which are listed in the process hazard analysis (PHA) report. Part of the design process is considering many what-if scenarios that examine what happens if various components fail. A safety integrity level (SIL) is a performance measure which tries to quantify the probability of a specific SIF failing to perform its required function when called upon, known as the probability of failure on demand (PFD). Whereas a DCS is performing process control functions continually while the plant is running, the SIS is dormant by design until required to perform a safe shutdown function. Table 1 lists four SIL levels and their related PFDs as defined by IEC 61508 and IEC 61511. All standards are not necessarily the same. For example, ANSI/ISA-S84.01-1996 recognizes only three SILs. Table 1: Safety Integrity Levels Techniques to establish the required SIL for a SIF in a SIS are defined in the relevant industry standards. (Some are listed in the online resources for this article.) SIL 4 is the highest level of safety integrity while SIL 1 is the lowest. The risk reduction factor (RRF) for a SIF is the mathematical inverse of the PFD_avg for that SIF. It represents a number corresponding to the factor that the SIF reduces the likelihood of the hazardous event that the SIF intended to prevent. Probability of failure on demand (PFD) is the probability that a SIF designed to protect a process plant will fail to shut down the plant safely when the hazard shutdown condition occurs. In other words, the safety function fails to do its job when called upon. Safety lifecycle The safety lifecycle, as defined by IEC 61508 and ANSI/ISA-S84.01, structurally defines a SIS development from its initial conceptual design through to its final decommissioning, as follows:

1. Conceptual design
2. Hazard and risk analysis PHA (HAZOP)
3. Safety requirements specification
4. System architecture and detailed engineering
5. Application programming
6. System production
7. System integration
8. Factory acceptance tests (FAT)
9. System installation and commissioning
10. Safety system validation—site acceptance tests (SAT)
11. Operation and maintenance plan
12. System change management
13. Decommissioning, and
14. Information and documentation requirements.

Generally, the significant hazards for equipment and any associated control systems have to be identified by the specifier or developer via a hazard analysis. The analysis identifies whether functional safety is necessary to ensure adequate protection against each significant hazard. If so, then it has to be taken into account in an appropriate manner in the design. Functional safety is just one method of dealing with hazards, and other means for their elimination or reduction, such as inherent safety through design, are of primary importance. IEC 61508 applies to safety-related systems when one or more of such systems incorporate electrical and/or electronic and/or programmable electronic (E/E/PE) devices. It covers possible hazards caused by failure of the safety functions to be performed by the E/E/PE safety-related systems, as distinct from hazards arising from the E/E/PE equipment itself. It is generically based and applicable to all E/E/PE safety-related systems irrespective of the application. The underlying assumptions of the standards recognize that the consequences of failure could have serious economic implications. In such cases the standard could be used to specify any E/E/PE safety-related system used for the protection of equipment or product. The scope of IEC 61508-1 goes into more detail. The range of E/E/PE safety-related systems to which IEC 61508 can be applied includes:

• Emergency shutdown systems
• Fire and gas systems
• Turbine control
• Gas burner management
• Crane automatic safe-load indicators
• Guard interlocking and emergency stopping systems for machinery
• Railway signaling systems, and
• Variable speed motor drives used to restrict speed as a means of protection.

Relevant means of implementing safety functions include electromechanical relays (electrical), nonprogrammable solid-state electronics (electronic), and programmable electronics. Programmable electronic safety-related systems typically incorporate programmable controllers, programmable logic controllers, microprocessors, application specific integrated circuits, or other programmable devices which could include smart devices such as sensors, transmitters, and actuators. In every case, the standard applies to the entire E/E/PE safety-related system. That could encompass, for example, a sensor, through control logic and communication systems, to final actuator, including any critical actions of a human operator. For safety functions to be effectively specified and implemented, it is essential to consider the system as a whole. The physical extent of an E/E/PE safety-related system is solely determined by the safety function. Working through the entire safety lifecycle is a major undertaking, but it is a process critical to the safety of people, property, and environment. Robert I. Williams, PE, is instrumentation and control systems manager at Brinderson, Costa Mesa, Calif.  Key concepts:

• Understanding process safety involves potentially confusing standards and acronyms.
• Working through the overall safety lifecycle is a major project, but the process is straightforward.
• Understanding a few basic concepts can help decipher the complexities of standards language. 

ONLINE Detail on IEC safety standards www.iec.ch/functionalsafety/explained/page1.htm www.isa.org www.isa-84.com]]> Process Control Plant Safety and Security May SyndicationType: Article SyndicationSource: CFE Media (in-house) SyndicationSource: Manufacturer - Emerson Syndication: Control Methods (PID Advanced Process Control) ArchivedSyndication: Safety Security (Intrinsic Process Machine Plant Arc Flash OSHA Personal Protective Equipment) Syndication: Process Instrumentation Process Sensors (Temperature Pressure Level Flow) Syndication: Codes Standards Regulations Tue, 14 May 2013 14:53:00 -0400 http://www.controleng.com/industry-news/single-article/industrial-wireless-monitoring-and-sensing/c8a6a8eb11204efa7f9e398bd9bd9672.html Applying industrial wireless applications to monitoring and sensing can serve as a risk management... Wireless technology is a constantly evolving area, especially for industrial users, which often makes wireless infrastructure deployments in industrial environments difficult. Before taking on such a project, facility operators need to be aware of the challenges from rapid prototyping of wireless sensors in an industrial environment and the best practices for radio frequency (RF) design in complex or harsh RF environments, such as manufacturing, industrial, or power generation facilities. The business drivers for this type of project can most often be associated with the transition from conditioned-based monitoring to performance-based monitoring. The conditioned-based monitoring approach typically means lack of on-line data to support diagnostics, and poor data alignment (such as with data residing in separate databases). In addition, the data points are usually collected manually, and the lack of continuous data does not allow for complex analytics or modeling. Implementing wireless sensor sets create benefits across multiple areas. For instance, scarce engineering resources can focus on data analysis rather than data collection from disparate sources and can concentrate on few degrading trends rather than every trend. Maintenance workers can reduce or entirely eliminate selected data collection rounds through placement of wireless monitoring sensors. The need for deep technical capabilities on-site and concerns about inconsistent diagnostic results due to experience levels of individual employees can be greatly reduced. By leveraging wireless technologies, operators can acquire critical component monitoring data in significantly higher volumes, reduce staff impact of making collection rounds, and focus those resources on data analysis and prognostics of issues. By implementing a wireless infrastructure and using it for the rapid deployment of new sensor types, operators can create significant advances in critical component monitoring. Clear wireless infrastructure design A haphazard approach to wireless infrastructure project strategy can create huge cost and end user satisfaction issues. Even with good performance parameters, failure can occur if they are for the wrong application. To design the project for success, start with a solid system integration approach and define the business case and a clear concept of operations (ConOps). At the very least, list and prioritize applications. The approach, business case, and ConOps should drive technical specification and help manage end-user and client expectations. With this in hand, the throughput needs can be defined. These will affect technical decisions, such as access point density, backhaul infrastructure, switching, power requirements, cable/fiber runs, and facility penetrations, among others. Next, focus on the RF design process. Major steps in the RF design process should include passive and active surveys. Start with a passive survey for RF data collection, spectrum analysis, building composition analysis, and the outdoor features/topology noted. The deliverable after the passive survey should be the preliminary design. Once complete, all of the data can be imported into the RF modeling software to generate the preliminary model and design. Once the preliminary design is finalized, the active survey can start at the facility. The active survey should validate the exercise for the preliminary access point placements. Measure the actual signal performance and confirm the final design approach. Once approved, it is critical to work with the plant information technology staff and engineer of record to formulate the build package and for iterative reviews of design during the installation process as issues arise. After commissioning, designers should return to the facility for testing and tweaking of the operational system for optimal performance. This last step is often overlooked but is critical for successful implementation. Critical infrastructure problem Critical infrastructures have their own unique monitoring needs that are not being met, but a strategically planned wireless infrastructure deployment approach may help alleviate some challenges. Critical infrastructure systems are increasingly a complex blend of old and new systems with varying tolerances and management requirements. Aging infrastructure is expensive to instrument, monitor, and maintain. Often, this causes accidents. New infrastructure has its own set of issues and can generate an unmanageable “firehose” of uncorrelated data. To complicate things further, today’s compliance requirements are reactionary and constantly evolving, and the market is flooded with fragmented point solutions. Right now, the industry lacks a clear “systems approach.” Accidents, shutdowns, and cyber attacks can occur with a failure to monitor and act, so a well-developed wireless deployment plan is even more important on a critical infrastructure project. Pervasive wireless network Facility operators often face aging, legacy equipment that may be “un-instrumented,” and data acquisition on performance and maintenance may be natively impossible. Being able to retrofit ad hoc instrumentation and communicate to gather data and metrics can allow for better operational monitoring and maintenance planning and reduce downtime. One solution is to develop ad-hoc (off- the-shelf) modules for sensor types (humid, temperature, vibration, pressure) to allow rapid deployment of wireless-based sensors to gather relevant data. This allows ad-hoc, short-term, or emergency surveillance of problem devices. Plus, it allows a modular approach to wireless sensor measurement in an aging facility environment without large-scale digital equipment upgrades. Beyond the delivery of voice over Internet protocol (VoIP) and mobile worker/data applications, the availability of a pervasive wireless network within the facility allows deployment of low-cost sensors and meters for tactical or short-term operational needs. A “bug-like” approach for the deployment of multi-sensor devices that is specific to the operation’s needs should be used. For example, if a faulty motor or pump is suspected, a camera, vibration sensor, and hall-effect monitor can be attached to the housing. In today’s market, the sensor takes three minutes to assemble the modules in the “plant shop” and one minute to provision on the network. Cohesive reference architecture One of the best ways to avoid wireless technology obsolescence, ensure a long system lifecycle, and maximize system utility is to select and deploy wireless infrastructure in the context of a cohesive reference architecture. A reference architecture’s chief function is to provide a baseline roadmap related to interfaces and capabilities of related technology systems and business processes for legacy and planning perspectives. Investing the energy and effort in development of a well-thought-out reference architecture provides several key benefits. These include ensuring equipment compatibility, adherence to and compliance with evolving standards across the enterprise, realization of long-term return on investment goals, and optimal planning of capital expenditure spending. In an industrial setting the major components comprising a reference architecture typically include field instrumentation, communications, storage/analytics, and presentation/visualization. There are dozens, if not hundreds, of field devices that can be connected using one or more wireless technologies. Capturing field devices in the reference architecture provides an easy method for managing the multiple interfaces that need to occur between field and communications devices. Similarly, management of the interfaces between communications networks to the analytics/storage and presentation/visualization layers is also important to capture in a reference architecture. This ensures that higher layer factors including communications protocols, application programming interfaces, interface libraries, and other critical communications functions are well understood and accounted for during the wireless technology selection process. Embracing wireless Although not without challenges, wireless solutions can act as a common enabling technology. They can:

• Provide ubiquitous communications capabilities
• Offer cross-operational value and utility
• Deliver common IP access using standards with robust cyber security
• Reduce lead time and costs associated with wired cabling. 

On many projects, doing nothing is not an option, so the wireless solution acts more as a risk management policy. Plus, a strong communications foundation can address many challenges facility operators face during process transformation. - Douglas Bowers is a senior project manager at SAIC. He has more than 15 years of experience in system integration for communication and network systems, identifying requirements, writing specifications, design, testing, and delivery, including rapid prototyping and development of sensor systems for industrial environments. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering and Plant Engineering, mhoske@cfemedia.com. ONLINE www.saic.com/EEandI  Bowers presented in a Control Engineering industrial wireless webcast. Learn more at www.controleng.com/webcast. www.controleng.com/wireless links to related coverage.]]> System Integration Tutorials Slider Homepage Item - CTL June SyndicationType: Article SyndicationSource: CFE Media (in-house) Syndication: System Integration System Integrators ArchivedSyndication: Industrial Networking (Wireless Ethernet Sensor Networks Fieldbus IoT) Tue, 14 May 2013 10:31:00 -0400 http://www.controleng.com/industry-news/single-article/digital-panel-meters/796914cc573134ab7cec72cccaf1833b.html Precision Digital's PD765 and PD8-765 Trident Series Digital Panel Meters are adjustable to... Precision Digital's PD765 Trident Series Digital Panel Meter is a process meter that features two relays, a 4-20mA analog output, and a 24 Vdc power supply all in one meter. It is housed in a shallow, 3.6-inch depth, 1/8 DIN enclosure that features a NEMA 4X front panel. Two display heights are available: the Trident 0.56-inch (14.2 mm) display, and the Trident X2 1.2-inch (30.5 mm) display. Each display is adjustable to lighting conditions, including direct sunlight. This allows the meter to easily be read from distances up to 30 feet. For hazardous area applications, the model PD8-765 integrates all the Trident meter functions into an explosion-proof, die-cast aluminum enclosure with through-glass SafeTouch buttons and worldwide agency approvals. The Trident panel meters are designed to handle a wide range of level, flow rate, temperature, and pressure applications. They can be field programmed to accept process voltage (0-5V, 1-5V, etc) and current (4-20 mA) inputs, 100 Ohm RTDs, and the four most common thermocouples: J, K, T, and E. The Trident meters feature a variety of options: two relays, a 4-20 mA output, 24 VDC transmitter supply, and serial communication with Modbus RTUprotocol. The 4-20 mA output option converts the meter into a transmitterwith a digital display, making it well suited for temperature applications. All functions can be set up from the PD765 front panel or from a PC running Precision Digital's free MeterView software. Configuration settings can besaved to a file for reporting or for programming other meters. Trident panel meters can also be set up using National Instruments' LabVIEW software. The PD765 is housed in a shallow-depth case that is designed for easy installation. The PD8-765 panel meter is housed in a die-cast aluminum explosion-proof enclosure. Precision Digital Corp. www.predig.com ]]> Process Control New Products HMIs and Operator Interfaces Industrial Networks Motors and Drives PLCs and PACs Sensors Process Instrumentation SyndicationType: Product Release SyndicationSource: CFE Media (in-house) Tue, 14 May 2013 09:51:00 -0400 http://www.controleng.com/industry-news/single-article/tear-down-the-walls-literally/25d5417d3afe34eacd65bf94337babab.html Walls in work areas can hurt direct and indirect communications for dynamic, fast-paced teams and... We got rid of cubicle walls around the same time we started moving people constantly according to their teams and projects. We didn’t do this for the whole office, but we realized that for our teams that work in a dynamic, fast paced environment, walls were hurting direct and indirect communications. Direct communications Lift you head up, see who’s out there to help, ask your question, get your answer, and go back to work. There is no need to get up and wander around if there are no walls. This may provide lots of short distractions but if you really need to focus, you can put on your headphones or ear plugs as a visual “do not disturb” sign. Quick impromptu meetings are easier for the same reason. It’s as simple as “Hey, come here, see this?” or “What are you up to? I don’t think that’s the right direction.” We don’t have to wait until tomorrow to find out time has been wasted. Indirect communications If you’re the project manager or team lead, and there is a delay in those familiar typing and clicking noises, your spider senses start to tingle. It’s easy to ask – “Hey are you stuck?” People venting and getting frustrated is always visible. If someone’s stuck, anyone on the team can see this and help. A face that is frustrated or unsure can’t be hidden without walls. “Stuck” time is lower and people are back to work before you know it. Sure there is more noise and sometimes you need to move to a different area for a client call or to focus on a task, but walls impede a healthy team environment – tear them down. - The Control Engineering “Automation System Integration” blog is written by Anthony Baker, a fictitious aggregation of experts from Callisto Integration, providing manufacturing consulting and systems integration. The blog provides Callisto Integration advice in plant-floor controls, manufacturing execution systems (MES), and manufacturing consulting, from the factory floor through to the enterprise. Andrew Barker, P.Eng., Callisto Integration, compiled the advice. See additional posts at www.controleng.com/blogs. www.callistointegration.com]]> System Integration Tutorials Slider Homepage Item - CTL Automation System Integration SyndicationType: Article SyndicationSource: Systems Integrator/consultant SyndicationSource: CFE Media (in-house) Syndication: Labor (HR Contracting Outsourcing Retention Knowledge Management) Syndication: System Integration System Integrators Tue, 14 May 2013 07:00:00 -0400 http://www.controleng.com/industry-news/single-article/build-os-neutral-mobile-interfaces-for-automation-monitoring-control-applications/9aa6042db560099898d8bd3c76ebfe7d.html Opto 22 groov is a new system for building simple, effective web-based interfaces to monitor and... “groov” is Opto 22’s new system for building simple, effective Web-based interfaces to monitor and control systems and equipment using computers and mobile devices. Using only a Web browser, groov allows fast design and deployment web-based automation, monitoring, and control applications that work on most computers and mobile devices regardless of operating system (OS). It allows mobile, visible, accessible, and simple screen development.
Opto 22 calls groov a “human device interface” (HDI) instead of a human machine interface (HMI) because it takes the regular HMI in a different direction: towards the tablets, smartphones, and other mobile devices that have become part of home and professional lives. Opto 22 developed groov with HMI best practices in mind, including those defined by the “High Performance HMI Handbook,” providing the tools to build high-performance, intelligible information and control screens. The new system is not intended to directly replace an HMI, but to augment HMI systems by making important information easily available on almost any mobile device or large, flat-screen HDTV, mounted high for monitoring key performance metrics (KPIs) or other parameters. Totally new software “This is unlike anything being offered,” Benson Hougland, Opto 22 vice president of marketing and product development, told CFE Media. All software is included, accessible via any browser, without plug-ins, without downloads, no per-user licenses, no tag limits, with nothing else to buy or install, Hougland explained. “This make software as easy as possible to use; groove Build has pre-drawn touch-screen-enabled gadgets,” Hougland said. Screens are distributed via an HTTPS URL with secure sockets layer (SSL) encryption. Prior attempts to mimic operator interface screens in a browser have been poor, Hougland explained, with limited scalability. This system uses HTML5 to scale graphics, buttons, labels, images, live video, trends – everything – to the screen size. The only software needed is a browser. On the development page for the software, another tab allows tweaking or reordering to optimize gadget location with screen shape, but scaling works fine, even without changes, as a demonstration showed. “Application development can be done quickly and is fully scalable, from large-screen high-definition television to an iPod Touch in kiosk mode, operating as a light switch,” Hougland said. It eliminates programming, reprogramming, and server commissioning and deploys changes automatically. App optimizes performance on smart phones and tablets groov View apps for iOS and Android control how groov browser-based operator interfaces are displayed on smartphones, tablets, and other devices. The free groov View apps are an optional part of the larger package. Using the groov View app instead of a browser visually simplifies the interface on a mobile device by displaying it full screen and without browser menus. This option focuses the user's attention on the operator interface screen by removing navigation buttons, favorites, and the URL bar visible in most mobile device web browsers, and makes a groov interface function like a native app for that operating system. The groov View app includes options to leave time and other device information visible at the top of the screen as well as to switch between the views-desktop or handheld-developed for the operator interface. User access to the operator interface can be password protected. The groov View app is ideal for OEMs and system integrators using an iOS or Android device as the operator interface to their systems or equipment. When used on iOS devices like the iPod Touch, iPhone, iPad, and iPad mini, the iOS operating system can be configured to limit the user to using only groov View for iOS. Generally referred to as "kiosk mode," iOS's Guided Access feature lets an administrator restrict the iOS device to a single app, disable the hardware buttons, and keep the device from sleeping, effectively providing a low-power, low-cost, wireless, touchscreen operator interface locked down for an intended use only. Product features The product consists of an Opto 22 groov: - Box – Industrially hardened appliance that interfaces with Opto 22 control systems and runs the groov web application. - Build – Web application’s mode for creating a groov project (the interface). - View – Web application’s mode for running a groov project in any modern web browser. - View for iOS – iOS app for groov View (optional). - View for Android –Android app for groov View (optional). Version 1 will be available in April for use with SNAP PAC controllers, and version 2 with OPC connectivity is expected this summer, Hougland said. Pre-orders will be taken starting March 13. - Mark T. Hoske, content manager, CFE Media, Control Engineering, Plant Engineering, and Consulting-Specifying Engineer, mhoske@cfemedia.com. www.groov.com  www.opto22.com  - This article was originally posted Feb. 28, 2013, with information from Opto 22 and updated May 14 by Peter Welander with additional information about groov View apps for iOS and Android.]]> System Integration Information Control Process Control Machine Control Sustainable Engineering Manufacturing IT Slider Homepage Item - CTL HMIs and Operator Interfaces New Products Industrial Networks Mon, 13 May 2013 22:33:00 -0400 http://www.controleng.com/industry-news/single-article/pid-math-demystified-part-2/a88740698bafaa3ed8d1d08ffc8a1ee0.html You’ve see the equations, but have you thought about how those elements work together? Part 2:... (Read Part 1) Now let’s look at the next part of the equation, the integral component: The most striking (and scariest) part of this equation is the big integral sign in the middle. If you’ve had high school calculus, you think to yourself, “I’ve got this. Integrals don’t scare me. I just need to find the area under the curve from time zero to time t of the error function.” But, this is the real world. What is time zero? How do I integrate an error function? The good news is that the real definition is much simpler than calculus. What the PID function does is take a portion of the error and adds it to a running total. This running total, sometimes called reset, is added to the output. Since reset increases or decreases a little at a time, it adjusts the output of the valve incrementally each scan.

For a PI controller, the two factors that we have covered so far are K_p and K_i, but if you look at the faceplate for most industrial systems, there is only one K (gain) that has no units, and a τ_i (integral time constant) designated as seconds or minutes per repeat. So, a little translation is required. Most industrial controllers don’t use the independent form of the equation shown above. Instead, they use the dependent form of the equation:  The K is typically the same as the proportional gain, K_p.  The factor τ_i determines how much of the error is going to be applied to the accumulated reset on each scan. So in the big mathy equation, K_i can essentially be replaced by the faceplate parameters:  K⁄τ_i.

What’s important to understand from this is that the gain that affects the proportional action of a controller also affects the integral action. But, the integral time constant τ_i only affects the integral action.

In pseudo code this would look like:

Error := Setpoint - ProcessValue;

Reset := Reset + K/tau_i * Error;

Output := K * Error + Reset;

The unit’s minutes per repeat for the integral time constant τ_i  comes from the fact that if the error stays constant, that is how long would it take for the integral accumulator to repeat the proportional change in output.

Note: Another way of specifying the integral tuning parameter is in seconds, and then it is the reciprocal of seconds per repeat. If the integral time constant is in seconds, the bigger the number, then the slower the response. If the integral is in seconds per repeat, the opposite is true.

Derivative

Now let’s look at derivative: Again, this is another mathy looking equation with a simple explanation. The mathy definition first, the output will be changed by the derivative (or rate of change) of the error function. What this means is that the output will be affected by the change in error from one scan to another. Adding this to our pseudocode gives us:

Error := Setpoint - ProcessValue;

Reset := Reset + K/tau_i * Error;

Output := K * Error + Reset + ((PreError – Error) * K/tau_d));

PreError := Error;  //Save the error for the next scan

What is intended is for the output to change as soon as the process variable begins to move either toward or away from the setpoint. What results can be a very quick response to a change in error from one scan to another.

The intention of derivative action is to respond to changes as they begin to occur. For example, if a temperature is starting to rise, the valve will begin to open as soon as it sees the change instead of waiting for it to cross a setpoint. This can result in a very rapid response to a small change. This rapid response can become unstable if there is noise in the process variable or on a setpoint change. So, the derivative action is often filtered separately and is sometimes calculated on PV only to ignore setpoint changes.

Summary

So now we have reviewed the three components of the PID algorithm. One way they have been described is in terms of the flow of time. P depends on the present error, I on the accumulation of past errors, and D on the prediction of future errors based on current rate of change. 

This post was written by Scott Hayes. Scott is a senior engineer at MAVERICK Technologies, a leading system integrator providing industrial automation, operational support, and control systems engineering services in the manufacturing and process industries. MAVERICK delivers expertise and consulting in a wide variety of areas including industrial automation controls, distributed control systems, manufacturing execution systems, operational strategy, and business process optimization. The company provides a full range of automation and controls services – ranging from PID controller tuning and HMI programming to serving as a main automation contractor. Additionally MAVERICK offers industrial and technical staffing services, placing on-site automation, instrumentation and controls engineers. ]]> Process Control Real World Engineering SyndicationType: Article SyndicationSource: Systems Integrator/consultant Syndication: Process Manufacturing Syndication: Control Methods (PID Advanced Process Control) Syndication: Process Instrumentation Process Sensors (Temperature Pressure Level Flow) Home Page Lead News Item Slider Homepage Item - CTL Mon, 13 May 2013 14:24:00 -0400