This tutorial presented by the University of Michigan's School of Engineering will show you the characteristics of proportional (P), integral (I), and derivative (D) controls, and how to use them to obtain a desired response.
In this 43-page eBook, Bela Liptak, control and safety consultant and editor of the Instrument Engineer's Handbook, describes the state of the art for controlling and optimizing the distillation process.
This white paper offers a critique of the state of advanced process control using model-predictive control, reviewing the developments over the last 25 years since the debut of dynamic matrix control in early 1980 and also the state of technology, both old and new, available now.
Sensing options enable users to choose the sensor most appropriate per application. However, making this choice is not often easy. This paper helps unravel the complexities and differences between sensor types and applications in which they are used.
Without measurement there is no control. As with any type of measurement, results need to be expressed in a defined and clear way to allow everyone to interpret and apply those results correctly. Accurate measurements and good measurement practices are essential in industrial automation and process environments, as they have a direct effect on the success of the desired outcome.
Pressure, the measure of a force on a specified area, is a straightforward concept, however, depending on the application, there are many different ways of interpreting the force measurement. This white paper will identify the various units of pressure measurement, while discussing when and why certain pressure measurements are used in specific applications.
The purpose of this article is to improve the understanding of tray cables by defining them, describing the five different types of tray cables and providing accepted uses and standards, including environmental considerations, for each of those types.
The operations and manufacture of biopharmaceuticals is a complex process combining the capabilities of multiple systems that extend the boundaries of batch processing. The Manufacturing Execution System (MES) receives information from the Enterprise Resource Planning (ERP) system and creates the necessary production orders, maintains material tracking/genealogy and coordinates key manual activities. The automated batch control system sequences the phases, controls the devices and captures the necessary history. These systems come together in the operation of Biopharmaceutical production plants, which require a very specific architecture that leverages standard batch products that are tightly integrated with MES capabilities. This is driven by the upstream and downstream processing specifications of such plants, the detailed compliance requirements and the benefits achieved in maximizing automated functionality. This paper explores the unique requirements of batch manufacturing in the biopharmaceutical environment.
With any new tech device, whether a cell phone or plant-floor controller, there is inevitably a helpful feature or two you overlooked while reading the manual or taking the introductory tutorial. Although these technological devices still perform their desired, basic functions - discovering an underutilized feature makes you wonder how you ever operated the device without it.
Interacting with alarms is one of the basic functions your operators expect from their human-machine interface (HMI) software. However, if you're only using the standard alarming functions, you may be missing out on lesser-known features that could help you save time, ease troubleshooting and reduce headaches. The five FactoryTalk Alarms and Events functions listed below are often overlooked and underutilized. See where they fit and if you can find some hidden tools in your plant-floor applications.
Changing market conditions are forcing batch-manufacturing facilities to modify the way they conduct business. The demand for software and hardware vendors to provide a higher level of batch automation is increasing. This demand is being fueled by a shortage of knowledge-workers coupled with the demand for flexible manufacturing environments. Industry standards for software and batch-control are emerging rapidly. These standards are helping to improve the interconnectivity of many products.
E-commerce will be the area for growth during this decade. Many companies are already buying and selling products through business-to-business portals on the Internet. The ability for a company to respond to ever changing manufacturing demands will determine their success or failure in the future.
The purpose of this paper is to discuss these business trends along with the impact of new standards on the batch industry. The paper describes several examples of companies that have been able to leverage infrastructure investments while successfully applying these emerging standards.
Tom Hosea, Batch Applications Specialist, OSI Software Inc.
The benefits of Advanced Process Control (APC) technology are deemed so significant that many manufacturing experts consider the use of APC a necessary requirement to remain competitive. A closer look into the technology may reveal the reason.
One of the difficulties of managing projects that involve several organizations is that the group has no pre-established procedures for handling actions that cross organizational boundaries. Read this white paper to learn tips that can resolve cross organizational boundaries.
Tom Clark Project Success Incorporated, www.projectsuccess.com
The upgrade of an existing operational plant to a new control system can be full of uncertainties, especially in the areas of operability, downtime, and benefit. Cabot Corporation recently upgraded their Treated Silica operations in Tuscola, Illinois to Batch software, new PLC processors, and an upgrade of the existing HMI's to the latest version of the vendors software. The previous system was using older PLC's with HMIs in a semi-automatic configuration. The system relied heavily on the operators to make critical batch decisions and mechanical equipment adjustments. Cabot utilized the services of a batch software provider/developer, who developed the new system using S88 standards. The system started up with minimal downtime and has delivered as promised.
The Units have seen as much as 30% increased throughput, production record keeping has become more accurate, and the product has become more consistent. These gains were achieved by the automation of a great majority of the operators former manual tasks, which included the use of batching technology and the addition of more automation equipment in the field. Additionally, to speed production and fulfill Cabot's production needs for greater throughput, recipe entry onto the batch list is now handled using specialized campaign software.
Tom Branch, Senior Project Engineer, Application Systems Engineering, Rockwell Automation; Todd Ray, Senior Process Engineer, Cabot Corporation
The Stuxnet worm is a sophisticated piece of computer malware designed to sabotage industrial processes controlled by Siemens SIMATIC WinCC, S7 and PCS 7 control systems. The worm used both known and previously unknown vulnerabilities to spread, and was powerful enough to evade state-of-the-practice security technologies and procedures.
Since the discovery of the Stuxnet worm in July 2010, there has been extensive analysis by Symantec, ESET, Langner and others of the worms internal workings and the various vulnerabilities it exploits. From the antivirus point of view, this makes perfect sense. Understanding how the worm was designed helps antivirus product vendors make better malware detection software.
What has not been discussed in any depth is how the worm might have migrated from the outside world to a supposedly isolated and secure industrial control system (ICS). To the owners and operators of industrial control systems, this matters. Other worms will follow in Stuxnet's footsteps and understanding the routes that a directed worm takes as it targets an ICS is critical if these vulnerable pathways are to be closed. Only by understanding the full array of threats and pathways into a SCADA or control network can critical processes be made truly secure.
It is easy to imagine a trivial scenario and a corresponding trivial solution: Scenario: Joe finds a USB flash drive in the parking lot and brings it into the control room where he plugs it into the PLC programming station. Solution: Ban all USB flash drives in the control room.
While this may be a possibility, it is far more likely that Stuxnet travelled a circuitous path to its final victim. Certainly, the designers of the worm expected it to - they designed at least seven different propagation techniques for Stuxnet to use. Thus, a more realistic analysis of penetration and infection pathways is needed.
This White Paper is intended to address this gap by analyzing a range of potential "infection pathways" in a typical ICS system. Some of these are obvious, but others less so. By shedding light on the multitude of infection pathways, we hope that the designers and operators of industrial facilities can take the appropriate steps to make control systems much more secure from all threats.
This application note describes how to use the Tofino Industrial Security Solution to prevent the spread of the Stuxnet worm in both Siemens and non-Siemens network environments.
What is Stuxnet?
Stuxnet is a computer worm designed to target one or more industrial systems that use Siemens PLCs. The objective of this malware appears to be to destroy specific industrial processes.
Stuxnet will infect Windows-based computers on any control or SCADA system, regardless of whether or not it is a Siemens system. The worm only attempts to make modifications to controllers that are model S7-300 or S7-400 PLCs. However, it is aggressive on all networks and can negatively affect any control system. Infected computers may also be used as a launch point for future attacks.
How Stuxnet Spreads
Stuxnet is one of the most complex and carefully engineered worms ever seen. It takes advantage of at least four previously unknown vulnerabilities, has multiple propagation processes and shows considerable sophistication in its exploitation of Siemens control systems.
A key challenge in preventing Stuxnet infections is the large variety of techniques it uses for infecting other computers. It has three primary pathways for spreading to new victims:
- via infected removable USB drives;
- via Local Area Network communications
- via infected Siemens project files
Within these pathways, it takes advantage of seven independent mechanisms to spread to other computers.
Stuxnet also has a P2P (peer-to-peer) networking system that automatically updates all installations of the Stuxnet worm in the wild, even if they cannot connect back to the Internet. Finally, it has an Internet-based command and control mechanism that is currently disabled, but could be reactivated in the future.