8 ways to improve control system projects

7/30/2019 8 Ways to Improve Control System Projects

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8 Ways to Improve Control System

Projects

Robert A. Dunlap, University of Texas

Control Engineering

April 1, 2003

Process control systems are growing more powerfuland more complex. And in the future they are expectedto integrate into plant- and enterprise-wide systems toan ever-greater degree.

The repercussions of these developments are significant: the net benefits a well-engineeredprocess control system can deliver are large. Conversely, startup and operational time lostthrough ineffective systems can be very expensive to recoup. Poorly engineered or slowsystems increase operator fatigue and can be dangerous.

Control system engineering should not exist apart from overall project and enterprisebusiness plans. Here are some ways to avoid traps in control system engineering projects.

1 Communicate before a visitDevelop a visit plan and communicate it to all involved before the visit. For example, doesthe client expect a demonstration of data passed to SAP modules? Will a list of XML tags besubmitted and agreed upon? Include requirements before travel so that the other party hasample time for setup. Is an analog phone line or conference room needed? Is the visit purelytechnical, or should time be allowed for a project schedule discussion? It is easy for another

party to arrange to accommodate a visitor beforehand. In contrast, it is expensive andannoying to make people wait for a crucial but simple request to be fulfilled.

2Emphasize operator-friendly graphicsPlant operators spend more time with the control system than anyone else. Apart from shiftsoutside or in the field, much or all of an operator's time is spent in front of a screen, dealingwith faceplates and graphics. Therefore, make sure this aspect of programming is solid andapproved/frozen first. The plant will operate without hooks to ERP, but not with dark glass infront of an operator.

The unprecedented power of NT terminals allows a lot of visual noise to be programmedinto displays. Complex machinery pictures, pipes with multiple colors and blink rates, andindicators that mock physical field devices look good in presentations, but increase operator


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fatigue and irritation. Avoid the temptation to cram too much information onto a display.

3 Test software intelligentlyTry to break the software: exception handling is key. For example, when testing dialogboxes, try to enter nonsense symbols instead of valve tags or setpoints. Open morewindows than recommended. The operating environment is different than the programmingenvironment; take into account that multiple keys will be hit faster than expected at exactlythe wrong time.

Real results are best. If testing a control system and recording results, use actual tagnumbers, verbatim messages, and detailed descriptions. This approach makes testingtraceable and repeatable, and is required in some industries.

Consider customer requirements. For example, before testing a PID controller, agreewhether a template, a single instance, or every instance needs to be tested. Somecustomers may not want templates of PID controllers tested. They may view this activity asa waste of project monies. A review of standard QA procedures should answer this question.

Remember that a process control software project is not just about the software. Percustomer agreement, some stage of testing should involve a small team that checks eachinput and output terminal and simulates and measures results. Loop checking afterinstallation is much easier, because most problems will be isolated to the field.Troubleshooting control software beforehand with a small team is much more efficient thanhaving an entire loop-checking team waiting for a programming change to be made. Openboth FO and FC valves. Check screen entities against the I/O list.

4 Let customers own the documentsTurnkey projects have certain advantages, but can cost the end customer more if notmanaged properly. Without customer ownership, the control system programmer mustinteract with multiple points of contact to try to resolve changes and clarify questions. Theend customer, with knowledge of all aspects of the project, acts as a filter.

For example, screen graphics are often drawn from P&IDs. These documents undergoseveral revisions during the course of plant engineering and construction, usually in tandemwith control system engineering. It would cost the system vendor a lot of time and money tocheck each revision and find that only a small piping change had been made. Keeping thecustomer in control can ensure higher quality. Software development is highly nonlinear,and involving multiple parties slows a software project considerably.

5Find out if the actual machine is neededCertain procedures and industry-specific requirements state that the machine that willoperate the plant be the one actually tested. Developers should periodically checkschedules with the operating company to ensure that engineering requirements do notconflict with their operating requirements. It is acutely embarrassing to hold up productionwhen your supposedly simple change will not compile and a product shipment is delayed. Iffacsimile terminals and control systems are to be used for testing, the end customer shouldbe made aware of it.


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6Link with Customer ServiceSometimes a user's complaint call is actually a favor for the software developer. Respect thefact that just by operating, the control system owner performs testing that is expensive forthem and cheap for the configurer. Operations staff sits at the control system constantly andfunctions as a real-time bug-catcher. The control system developer's Tech Service and/orCustomer Service departments should be directed to flag a user's calls and copy them to theteam performing that user's programming.

7Get participants to 'buy in'If the software upgrade is small and has few effects, a simple memo to those involved (IT,Operations, Engineering) may be all that is required before the change is made. Considerdegree: no one likes being surprised with a totally new environment. Ask operators for theirinput on graphics and meet with IT personnel on how best to connect to the plant's physicallayer. Consider timing as well. In a batch process, an upgrade or change can be performedquietly; in a continuous process, extra precautions must be taken.

8Wait for upgrades, service packsEngineering a control system is not a trivial project. It will typically occupy many months.Operating system upgrades and vendor upgrades will certainly occur during the projectscope. Wait until after important milestones to perform upgrades. Such planning makes iteasier to isolate problems associated with an upgrade.

Comments? [email protected]

Author Information

Robert A. Dunlap is an MBA candidate at University of Texas (Austin).

Follow These Steps to Control System Project Success

Taking a few simple precautions in the early stages of project development can go a longway toward ensuring success of the effort. Here are eight steps to take:

1. Set expectations before traveling to or visiting a site.

2. Emphasize the system's graphic interface; operators spend much of their time infront of a screen.

3. Test software intelligently; if it can happen, it probably will.4. Remember the end customer should own the I/O lists, P&IDs, and other

documents; keep the customer in control.5. If the actual machine needs to be tested, be sure it is available and accessible.6. Connect with the customer service staff; they can be a wealth of information.7. Encourage all involved to buy into the project by keeping them informed and

soliciting their input.
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8 ways to improve control system projects

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