Author : Michael Babb
Sunday, December 6, 2009
Standing at the edge of any modern chemical processing plant, one cannot help but be impressed by the great complexity of the equipment in the surrounding landscape. In the control room, this complexity is mimicked on the screens of the DCS, and must be guided by human operators.
Running the system, especially during startups and shutdowns, can be difficult and dangerous. Integrating the DCS with other systems at the plant is a difficult problem for the engineers. Optimising the operation for the maximum benefit of the business is the task of the managers. So far, nobody has found an overall solution.
A systems integration firm in Houston, called PAS, thinks it can resolve these problems by gathering the relevant data and organising them into a database. The privately held company, which was founded in 1993 as a systems integration firm, has 110 employees and spends about 20% of its budget on R&D.
This massive new database includes everything from engineering construction diagrams, DCS and PLC configuration software, safety system data, and even what it calls ‘empirical’ data—information understood by only a few persons, learned directly from the process. The empirical data can be picked up from e-mails shared among the engineers about changes in the system.
PAS’ system is the “Big Brother” for process automation systems. It’s watching everything, and recording it too. If you’ve made a configuration error, it will find it.
Staggering complexity
The task of understanding modern process automation has become so onerously complex, Chris Lyden, president of PAS compares it to ‘genetic’ structures of the human genome. PAS’ goal, he says, is to ‘map’ the ‘automation genome.’
In contrast with human genomes, which came about by the magic of undirected natural forces, an enormous amount of engineering effort must be expended to construct the automation genome.
The main thrust of this effort is PAS’ Integrity software, which looks at the various control systems, identifies relationships and hierarchies, and ‘normalises’ the data into an aggregate database.
Individual control systems may be well documented, but often the relationships between control systems, and between control systems and the IT department are less well understood. Plus, there is an ever expanding portfolio of advanced applications and production management packages which have involved engineering investment many times greater than their original cost.
And the relatively few people who understand these connections are leaving the companies, for retirement. The type of knowledge they have is called “empirical” because it is understood by only a few, and they learned it directly from the process. It may not be written down anywhere, or if it is, it’s hard to decipher.
It may be knowledge like “this pump gives off a certain sound before it goes into cavitation.”
All of this escapes the attention of cost-cutting accountants, who sometimes display little sympathy for the needs of engineers.
But some of them may start to pay attention. One leading U.S. refiner recently reported losing 2,500 man-years of operator experience through retirement at a single site in one year, while a major chemical company said that it expected to lose 75% of the operating staff at one of its largest plants through retirement by the end of the decade.
Engineering added value
Mr. Lyden says the most important aspect of the engineering ‘added value’ is the production knowledge which is embedded in a plant’s automation assets as a result of their configuration and operation. Such knowledge may range from process chemistry in the form of formulae and recipes to control strategies and automated procedures.
It may also include the proprietary techniques from which an organisation derives its competitive edge and the means by which it fulfils its environmental and safety responsibilities.
Such knowledge is continually added to and refined over the life of a plant. Automation systems are worth more at the end of their life than at the beginning.
“With plant automation systems having grown in complexity from a few hundred measurement points in the 1960s to a few hundred thousand today and process management applications often numbering 150 or more, it’s a challenge which has been likened to mapping the human genome,” says Mr. Lyden.
“And it has the added complexity that the ‘Automation Genome’ is continually changing as a result of integration and interaction.”
That is a key difference. Human genomes are stable for thousands of years; over a period of decades a human will pass on 99.99% of his or her genome to the next generation, whereas the information describing the automation system is in a state of continual change.
The Asset Model
He says PAS’ Integrity software “maps” everything in the automation system, field instrument databases, DCSs, PLCs, and pure software assets such as historians and advanced process control or process management applications.
The key part of Integrity is the “Asset Model,” which is dedicated to a particular brand of automation system. These are driver-like plug-ins that convert the source data into a common data format for the Integrity database. Currently PAS has more than 40 Asset Models are available, covering not only most popular DCSs, PLCs and safety systems but HMI/SCADA packages, historians and asset management packages.
There is a specific asset model for Honeywell’s TCD3000, another for the Experion systems, another for ABB and Invensys systems, and so forth.
Integrity came from previous generations of automated documentation packages, DOC3000 and DOC4000, developed for Honeywell systems. With the different Asset Models, the software can be adapted to different systems.
“And it’s not restricted to what would normally be regarded as automation assets but can capture knowledge from paper based and even human sources and handle it in essentially the same manner as that from electronic sources,” says Mr. Lyden.
“It captures and archives explicit knowledge from each source, mapping the genealogy of the dataflow, and also provides a set of common search, query and reporting functions.” The $175,000 mistake
Eddie Habibi, the CEO and founder of PAS, says that just having accurate and reliable documentation of an automation system is in itself an asset. PAS’ model can be quickly checked for errors in logic, or disconnections where there should be connections.
He gives the example of a major American petrochemical facility which, because it had extended its periods between maintenance shutdowns, forced the safety technicians to test the safety equipment while the system was operating.
They had no other choice.
The online interlock testing procedure called for bypassing a SIS (Safety Instrument System) output, and increasing the transmitter value in order to test the interlock.
As expected, the interlock in the SIS tripped, showing that the safety system was working properly. Because the output had been bypassed—the wire going to the safety valve in effect had been disconnected—the safety shutdown valve did not operate. Which was exactly what the safety team had planned to happen. They didn’t want their testing to trigger a shutdown.
Alas, the safety testers were not aware that there was a configured link to operator start-up assistance logic in the DCS, and when the DCS logic sensed the interlock trip, it placed all controllers in manual, and set all valve outputs to the fail-safe position.
In other words, because of inadequate documentation, the online safety testers shut the plant down. Production loss was estimated at $150,000. Added to this was the cost of regulatory fines from the environmental excursion, another $25,000.
When Integrity maps the automation genome, it exposes “genetic defects” such as configuration errors that may cause problems, says Mr. Habibi.
“A measurement point with emergency-level alarm priority should show up somewhere in the system,” he says.
“They were pulling a value out of the safety system and sending it over to the DCS. It’s where you cross these boundaries that troubles arise,” says Mr. Habibi.
Things like this that have been added to the system over a period of time will show up in the automation genome. This is especially important for legacy systems that have had a lot of equipment added to them.
The more data, the better
Not content to suck in data through the Asset Model, PAS has several other tools to add to its database aggregation.
To pull in data from outside the automation files, there is a “Smart Links” that connects text in Microsoft Office documents to the Integrity database, and an “Email Explorer” which aggregates emails in the Integrity database where they can be searched in context.
A “Defects Finder” automatically identifies configuration errors and a “Change Tracker” maintains a history of configuration changes.
“Spares Capacity” maintains a central inventory, identifying spare hardware capacity, and allows spares to be reserved against projects.
Honeywell a big customer
Mr. Lyden says Integrity draws on experience from 800 installations of previous generations of PAS technology which are currently mapping the genomes of some 3,500 process automation systems.
“Honeywell users, in particular, have enjoyed the benefits of the PAS approach, originally with the DOC3000 documentation system for TDC 3000 systems and, more recently, with the Integrity derived, Honeywell specific DOC4000,” he says.
“And now, following a successful nine month pilot, Invensys Operations Management has announced plans to integrate Integrity and to offer it to customers as their final as-built documentation on new systems.”
High hopes
Mr. Lyden has high hopes for the future of Integrity.
It provides the opportunity for process manufacturers to regain control of their automation investment by aggregating and reconciling the data from their disparate systems and transforming previously isolated pieces of information into contextual knowledge,” he says.
“It tracks changes to and finds errors in automation databases, maintains system documentation in real time, exposes hardware and software inventory and spare capacity and provides central backup and disaster recovery for all of a plant’s systems.
Recovery of systems is important in the Houston area, where hurricanes occasionally come in and do their damage.
But retiring personnel can also take a toll on a company.
“Arguably most importantly, at a time when the average age of automation related personnel is approaching 50, it captures their empirical knowledge and ensures that the organisation’s intellectual property doesn’t leave when they do.
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