Three steps to improving your processWhite paper: ABB Process Automation Services

Automation systems are designed to provide safe, reliable service for many years. But, as will all mechanical and electrical equipment, performance will degrade over time. No production process runs well forever. Due to the normal wear of the production equipment, the process will eventually begin producing off-specification product. The process may also respond poorly to changes in operating parameters, materials or environmental conditions, also leading to sub-optimum performance.

Not so long ago, facility managers had access to a staff of experienced process engineers within their organization. These process improvement experts devoted their time to analyzing production processes. They could be relied on to keep processes optimized, and uncover opportunities to increase efficiency, reduce costs, accelerate processes and improve quality.

Unfortunately, the payback for their efforts was sometimes not readily apparent or not realized quickly enough. Faced with increased competitive pressure and the need to very tightly manage costs, many of these process experts were let go or given other assignments that offered a faster or more easily identified return on investment.

Plant managers, however, still need access to the unique technical skills and knowledge required to maintain their

process efficiency and effectiveness. They can turn to the Original Equipment Manufacturers (OEMs) or other third-party optimization experts to provide assistance. These outside resources can be called on to solve acute process problems or issues, and to uncover opportunities to elevate a well-running process to even higher levels of performance.

Every manufacturing process has problems or issues of varying severity that reduce productivity, lower product quality and increase operating costs. Every process presents opportunities for improvements with measurable and often impressive results.

Identifying process improvement opportunities requires a three-step process:

− Diagnose the process − Implement improvements − Sustain performance

This three-step process is applied by optimization engineers to better understand a customer problem or need, identify and implement corrective action, and ensure that the improvements are maintained over time.

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Optimization engineers from the OEM or third-party service organization are typically selected for an assignment based on their experience with the specific process. Process generalists don’t have the in-depth knowledge to most efficiently analyze and correct process issues. These process specialists arrive on site equipped with an in-depth equipment and process familiarity that enables them to approach their investigation in the most efficient manner possible and quickly develop appropriate solutions. Collect DataDiagnosing the problem requires a series of steps that begins with data collection. The optimization engineers’ objective is to gather as much data as possible. More data generally provides better results, leading to a faster and higher-value process improvement.

“They first determine whether usable data already exists,” says ABB Senior Optimization Engineer Pete Tran. “Most useful data may be stored in a data historian, an archiving tool that captures and stores information for later analysis. Unfortunately, most process owners maximize the amount of data their historian stores by removing much of the detail needed for problem analysis. While the historical data may be of no use, optimization engineers can easily reconfigure the customer’s historian to begin collecting new, uncompressed data.”

Most process automation systems installed in the last 10 to 15 years are OLE for Process Control (OPC)-based . This data communication standard makes it very simple to download process data from any OPC-compliant device or system.

There are still many proprietary process control systems in use, containing possibly useful - but non-standard - data. Experienced optimization engineering firms have converters or translators that enable them to access the data resident in these legacy systems.

“There may also be off-line data, such as the results of the regular product testing done in a lab environment,” according to Tim Murphy, Senior Optimization Engineer, ABB Services. “However, this data is typically not very useful. Online data taken directly from the process is captured in a steady stream at a relatively high sample rate of one data measurement every second or five seconds. Lab data, on the other hand, tends to be more along the line of one sample every hour.”

Look for CorrelationWhile data collection requires special expertise, it is the easy part of the process and within the abilities of most process owners. What they lack is the analysis tools and expertise to turn that data into information that enables analysis. The raw data is nothing but that: masses of numbers. In the hands of skilled optimization experts, those numbers hold the answers to maximizing process performance. Teasing out those answers is a complex undertaking.

“The optimization engineers process the data to help visualize issues, making patterns or trends more apparent,” says Kevin Starr, R&D Manager, ABB Process Automation Services. “The human eye is very good at identifying problems when they are properly visualized. It‘s like a doctor reading an x-ray. There‘s no numerical analysis of the bone to say it‘s broken. Rather, it‘s all visual. The same concept applies for the validation and verification of a pattern in the data.”

Using a variety of mathematical, statistical and analytical tools, optimization engineers search for data points or trends that relate to the occurrence of the problem. One of the most commonly used tools is cross-correlation, based on the search for a certain pattern in the data that relates to a process variable: “When A occurs, B also occurs.”

“The investigation process generally narrows the hundreds or thousands of potential problem points to a very small number of variables, typically one or two,” says Tran. “Even in complex processes where many things can affect quality, it’s possible to narrow the field of candidates to isolate the suspect variables or factors that have the potential to elevate performance and quality. At this point, those variables are still only suspects, innocent until proven guilty through process testing.”

Conduct a Test PlanThe data may reveal issues in a variety of places. It could be found in:

− Process instrumentation, the devices that measure produc-tion parameters

− Process controllers, the software that looks at the inst-rumentation, compares it to a target, and calculates the desired actuator setpoint change

− Process actuator, the motors, pumps, valves or other me-chanical devices.

Based on the type of process, and the location and type of issued detected, the optimization engineers will develop a test plan that may include invasive and/or non-invasive tests.

The first course of action is non-invasive testing which involves collecting process data during normal production, with no changes introduced by the optimization engineers. This is a useful testing approach, but it may not be able to isolate the individual process interactions needed to identify a specific process issue. If non-invasive testing doesn’t provide the needed results, invasive testing is employed.

“One of the most common tests is a step test,” Tran says. “Optimization engineers vary the independent variable – their “prime suspect” – up and down to see how it affects the dependent variable, the condition or parameter related to the process problem.”

While the word “invasive” sounds like this test involves a major process disruption, the testing is coordinated with the customer to limit the magnitude of changes made so that the process remains within the current product specifications. That means little or no off-specification product will be created during the testing.

The results of the step test are often represented visually in a performance curve showing the interaction of the two variables. In some cases the performance curve takes the shape of a V. The point of the V indicates that there is one optimum condition or operating point for the independent variable. A bowl-shaped curve indicates that there is a broad range of conditions for the variable that will provide satisfactory production performance.

The performance curves provide continued benefit at end of the problem resolution process. The pre-improvement curve can be readily compared to the post-improvement curve to confirm the success of the effort, or to point out the need for continued problem correction.

“The success rate of optimization engineers after the first test is generally very high,” Murphy says, “in the 80% success range. However, there are always cases where the first test plan generates more questions than answers. It is sometimes, therefore, an iterative process, requiring a reconfiguration of the data gathering or a second attempt at correlating the data to the production issue.”

Diagnose the process

Paper Mill Optimization Savings Add Up. One of the three machines at papermaker’s South Carolina facility wasn’t able to transition quickly enough between products. As a continuous process, this meant mountains of off-spec material was produced during the transition. ABB Optimization Services experts relied on the Transition Fingerprint process to identify both hardware and software issues. Following optimization, transition time was reduced from 33.4 to 23.3 minutes, generating material, energy and other savings of $387K/year.

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Implement a solution Sustain the improvement

Once the process improvement work is complete, process owners typically assume everything will remain in an optimum state. However, future process adjustments, product changes or raw material substitutions can all lead to degradation in the recent process improvements or create entirely new problems.

As a closing step in the original corrective process, the customer can contract with the optimization engineers to provide some sort of automated monitoring to identify and ward off results erosion. The data collection systems used for the original diagnostics step are typically left in place, providing faster access to the data needed to analyze new issues as they arise, avoid results erosion and ensure that the improvement will be sustained.

“The process owner can choose to implement continuous monitoring of their systems by outside optimization engineers,” Murphy explains. “Continuous monitoring allows periodic reviews of the process and compares it to the benchmarks established in the test phase. Where the customer will allow a network connection to their process, optimization engineers can rely on remote monitoring to gain visibility to the system at any time and from any place. This enables the optimization engineers to monitor the performance of the system and provide remote consulting.”

These remote connections are typically accomplished via the Internet. While there is tremendous value in this remote access, these links should never be established before potential security issues are thoroughly considered and addressed. The process must be protected from hackers, viruses and other attackers.

The customer can negotiate the appropriate outside services to sustain the improvement in their process, and can select weekly or monthly remote assessments of system performance. If the optimization engineers detect results erosion or new potential issues, they can address them proactively, often before the issue is evident in product quality. They can often aid or direct the customer’s in-house process experts to help them quickly resolve the problem.

While the expertise and resources brought to bear by the optimization engineers are useful in diagnosing issues, their greatest value is realized in implementing the found improvements and ensuring their sustainability.

The implementation plan provided should provide recommendations for resolving performance issues and/or the steps required to maximize performance. Based on the testing results, these recommendations can include adjusting, replacing or upgrading equipment, or configuration changes like fixing incorrect settings or mismatched firmware revisions.

The recommendation typically includes a number of potential improvements or changes. To guide the customer, each recommendation should be ranked or rated, including an expected Return on Investment.

Beyond the basic process remedies, there are many other facets of a thorough implementation plan. It should specify activities going forward that are targeted on improved stability, efficiency and consistency in maintaining the system. Revised maintenance practices and procedures should be developed and conveyed to the process owner for implementation.

The implementation plan should also identify environmental issues that may adversely affect the satisfactory future performance of the process. Corrective action should be defined so that the process owner can take the appropriate corrective action.

Finally, the plan should include recommendations for any training required by the customer to ensure that their personnel have the necessary skills and knowledge to maintain the process improvements implemented.

Depending on the scale of improvements identified in the implementation, the OEM or third-party process improvement expert may present the implementation plan in a phased approach. Presented with a prioritized list of potential improvements, the customer can immediately implement the highest-return activities and delay the lower-value activities until time and budget constraints permit implementation.

For more information please contact: North America Customer Service Center29801 Euclid AvenueWickliffe OH 44092 1832, USATel: 1 800 HELP 365(1 800 435 7365) Option 4Outside USA/Canada: +1 440 585 7804Fax: +1 440 585 5087E-mail: NAService_info@us.abb.com www.abb.com

ConclusionHealthcare experts are unanimous in their advice that individuals should have regular examinations to achieve optimum health and longevity, rather than waiting for a problem that requires inconvenient and expensive emergent care.

That scenario plays out precisely the same with manufacturing processes. Outside optimization services are often called in only to solve acute problems like poor quality or low productivity. Tran says they are equally valuable in addressing chronic, but often unseen, hindrances to an optimized process. In almost every process, regardless of how stable or reliable it is, there are opportunities to advance its performance. OEMs and third-party engineering firms can apply the tools and insights needed to bring about major, sustainable process improvements that deliver an impressive return on investment.

“Inviting optimization experts to investigate a process typically results in some combination of enhanced quality, reduced costs and shortened production time, all of which may provide a business advantage, “Tran says. “Most plant managers are surprised when they discover the improvement – and fast return on investment – from optimizing a process that has no apparent problems.”

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