Optimizing Maintenance through Information

Nov. 1, 2011
Establishing an efficient and effective maintenance team requires sufficient and timely information.

Sensors with increasing intelligence, instrumentation, digital networks and advanced diagnostic algorithms combine to provide the tools necessary to accomplish the task. All of these tools produce large amounts of information that usually get locked away into large database vaults.

Writing on the concept of “Big Data” in the November 2011 issue of Popular Science magazine, Rena Marie Pacella says, “A database isn’t a vault—it’s a garden.” This statement excellently captures modern trends, even in industrial automation applications. Information should be cultivated and picked in various units to provide nourishment for optimizing manufacturing—both the utilization side and the availability side. Here, we look at cultivating information such that the efforts of the maintenance team may be optimized so that asset availability may be improved.

You might think that it takes a very expensive and time-consuming software project to accomplish a major upgrade that provides better asset performance and monitoring. But how about a smaller project whose results are “more reliable and accurate plus more mistake-proof, [where]critical audits are better, and make the job so much easier?” Mike Moyer, corporate quality manager for Solar Atmospheres, a global vacuum furnace OEM and commercial heat treater for the aerospace industry, uses those words to describe a recent project.

“I’ve been in the business for 22 years, and the recorders that Eurotherm (a part of Invensys Operations Management (www.invensys.com) the Plano, Texas automation supplier) has devised are one of the best monetization retrofits in our history,” he says. Solar Atmosphere’s furnaces must operate in accordance with the SAE AMS2750 standard for heat treating metals. The company’s previous monitoring system involved a paper-based strip chart recorder connected to nine thermocouples configured into zones. There would then be lots of data on the strip of paper, and manual data entry into a spreadsheet. Then someone would have to find the high and low thermocouple in the period, and look at the thermocouple certifications to make any necessary corrections.

After the retrofit, a video graphic recorder captures the data. Engineers open a utility, add the thermocouple correction factors plus other data (such as which furnace was measured), then the utility adds it all in and exports a report that is in line with AMS2750 reporting requirements. Implementation was not very difficult and “using the system was easy” says Moyer. “Everyone has PCs, so this was just one more application on a PC to check.”

Moyer says the new system makes the job much easier. “In the past when a job was done, we’d tear off the paper and attach it to the order to make it a part of the permanent record. But it was just marks on a piece of paper. Any analysis had to be done manually,” says Moyer. “Today we can enter batch times and track the data down later. We had some qualms about acceptance of digital data versus paper, but our customers had many younger engineers who had already embraced digital technology. They embraced this with open arms.”

Kim Cousteau, director of product marketing for Avantis (http://iom.invensys.com/EN/Pages/Avantis.aspx), a part of Invensys Operations Management in Burlington, Ontario, adds, “The key is being able to capture all that information and keep track of not only the data but also the records around assets. One idea we’re working on is a ‘heat map’ concept to graphically display by criticality those areas in need of attention. Then we display the next action that must be taken. The heat map considers the criticality of the asset, plus information on the condition. This hardware/software solution aids maintenance productivity by transforming data into information.”

Honeywell Process Solutions (www.honeywellprocess.com), the Phoenix process automation supplier, is also polishing its asset manager solutions, according to Chris Stearns, product manager for advanced solutions. “The idea is to take data and put it in format so the user knows where to focus time and attention. They might have thousands of instruments, but no way to figure out what’s the most important thing. Or maybe maintenance is causing a problem while trying to be proactive,” says Stearns.

Focus on wireless

Stearns notes that the large amount of rotating equipment, and consequent vibration analysis, in a plant can be a challenge. “The larger motors or turbines might get attention, but lots of others might not. Maybe tech goes around once a year or so to check things out,” he says. “So, we’re focusing on wireless to get that information. Managers don’t want highly trained techs wandering around just gathering data, so we do monitoring and have models to create a simple health index and combine that with other data to determine whether to send a fault alert. Then having the data, the tech can determine what to take out to the asset.”

At ExxonMobil’s Singapore Chemical Plant (SCP), management looked for ways to automate the monitoring and maintenance of pump vibrations to avoid unnecessary shutdowns that negatively impacted plant performance. Often times, pumps were running until a failed status situation occurred, without any alerts to trigger the operator to take necessary actions.

The plant wanted to avoid having operators physically visit the pump location to record the vibration records at periodic intervals. It needed a reliable solution that would help engineers monitor and view the vibration status of running pumps continuously in the distributed control system (DCS)—enabling them to be prepared for any predictive actions for pump repairs or servicing.

SCP turned to Honeywell and its OneWireless solution to perform pump vibration monitoring by bringing in the signals via wireless technology so that all vibration signals could be monitored comfortably from the central control room environment. This would also help further enhance the individual pump information by providing necessary data for prompt servicing and maintenance.

Honeywell worked with ExxonMobil to deploy the OneWireless solution by integrating it with the SKF vibration monitoring system to meet their stated objectives. Honeywell managed the entire project, which included an in-house contractor for hardware installation and third-party SKF vendor to provide a pump vibration monitoring system.

The benefits experienced at the plant after implementation included:

  • Made daily site checks by operators unnecessary, saving more than an hour/day from the entire process.
  • Enabled the plant to take preventative action well ahead of equipment failures and minimized any damage.
  • Integrated pump data into the DCS, allowing for data analysis and predictive measurement to estimate the feasible service duration for routine servicing.
  • Enhanced the lifecycle of equipment and reduced possible downtime.
  • Reduced project wiring costs with wire-free implementation. saving about 20 percent in wiring costs.

Continuing the theme of getting back in the race with networking, databases and visualization, consider the example from another industry—lime producing. Singleton Birch Ltd. is the U.K.’s leading independent lime supplier, with a product range that includes quicklime, hydrated lime, natural hydraulic lime, graded chalk, aggregates and other specialist products and services. Singleton Birch called upon the services of Rockwell Automation (www.rockwellautomation.com) and its system integrator InControl Systems (www.incontrolsystems.com) to develop a new site-wide infrastructure for its U.K. site in Melton Ross, Lincolnshire that could be accessed from a single point.

The existing infrastructure included five disparate DataHighway+ networks of Allen-Bradley SLC controllers. This fragmentation meant that, in order to diagnose problems, electricians had to carry laptops with RS232 communications around a very large area controlled by more than 30 PLCs. They also had to do individual backups using USB Flash memory keys.

A lack of a central repository for master backups resulted in lost comments and a poor disaster recovery plan. This was compounded by a lack of change control and audit trail, coupled to inexperienced electricians making unauthorized ad-hoc changes to control systems. This, in turn, could result in a lack of product quality traceability issues—especially those when related to the control system. Engineers also found it difficult to get online following modifications on other laptops and then they had no remote access. This resulted in frequent onsite call outs.

Ken Hebdon, electrical engineer for maintenance and projects at Singleton Birch summed up his company’s needs very succinctly: “I wanted to pull it all together and network the lot so I could access it from one place, either on or off site. I wanted a network that would let me talk to all the controllers and associated hardware from my computer in the engineering block; and I wanted to make this information available to all the electrical and mechanical engineers on site.”

Ethernet access

The first step for InControl Systems was to facilitate access to all of the existing control and SCADA nodes via the site-wide Ethernet network. From a software perspective InControl Systems recommended the installation of FactoryTalk AssetCenter from Rockwell Automation, which provides users with a set of asset-centric focused tools to securely and centrally manage factory and process automation production environments. It does so by securing access to the control system, tracking users’ actions, managing asset configuration files, configuring process instruments and providing backup and recovery of operating asset configurations.

 “Using FactoryTalk AssetCenter,” Hebdon explains, “I can access the network remotely, and issues or required code changes are resolved much quicker. We also have a total audit trail now, which documents the date, the time and the person making the changes—all overseen by a permissions-based system, which I have control over.”
“The solution was up and running very quickly,” Hebdon elaborates, “and disaster recovery is now a lot easier. Everyone bought into it quickly and appreciates the extra tools we now have at our disposal for fault finding. The technicians have 24/7 access, but can only diagnose the faults or issues, leaving only those with the necessary permissions to do the code changes.”

Due to this new system, Hebdon reports that callout hours have been reduced by 95 percent, and they’ve seen an 85 percent reduction in the time needed to resolve problems. “Everything is now readily available to the engineers, and they are finding programming especially straightforward,” he adds.

Power plant optimization

Yet another digital networking technology that enables maintenance teams to keep the asset on the track is Hart, and its companion WirelessHart, promulgated by the Hart Communication Foundation (www.hartcomm.org). Wisconsin Energy (We Energies) found these connectivity technologies to be just what the doctor ordered.

As the largest utility-owned co-generation facility in the country, the company’s Valley Power Plant has a unique need for reliability. Also, where others may be able to get replacement power with other plants on the grid, if the Valley Power Plant “loses its District Heating Steam System much of downtown Milwaukee will be without heat,” says Todd Gordon, computer instru­ment technician leader at We Energies’ Valley Power plant in Milwaukee.

The plant, which began operations in the late 1960s, produces steam and electric service. Two steam units, each with its own pair of boilers and a single extraction steam turbine-generator, each generating capacity is 140 MW of electricity.

In his 30-plus years with We Energies, Gordon has helped the coal-based co-generation facility convert its automation platform from analog control to microprocessor-based distributed control. In that time, Hart Communication has grown from use with handheld communication devices in the 1980s to laptops to a permanent connection with asset management software running in the control room. Now, Hart-enabled intelligent valve positioners, also called digital valve controllers (DVCs), play a key role in providing the reliability  We Energies needs for all life-cycle phases of operation: design, construction, device configuration, loop check, operations, maintenance, troubleshooting and insurance compliance testing.

“Hart smart valve positioners have been used since 1999, and have provided valuable diagnostic capabilities that have allowed us to troubleshoot problems while the valves are in operation,” says Gordon. Hart technology has also extended service live when installed on several older but still-viable control valves.

“In instances where we have installed a Hart-enabled DVC on an older valve, my experience is that it makes a bad valve work better until a replacement can be installed. The nice thing is that we not only succeeded in deferring a capital expense this way, but when we decide the time is right to replace the older valve, we can also transfer the DVC from the older valve to the new valve assembly,” says Gordon.

From initial handheld device-based communications, the company employed a laptop computer loaded with valve management software. For example, when control room operators identify a valve that is “leaking through,” or not shutting off completely, a technician can connect the laptop to an offline valve, stroke the valve, and compare its action and “signature” with a prior benchmark to pinpoint problems.

By 2005, the plant upgraded the laptop-based predictive maintenance software on the laptop, enabling it to communicate with Hart smart devices to the DCS via multiplexers. This empowered instrument and control personnel to monitor smart devices online from a single location and gather information on their condition—remotely while the process was in operation. Evaluating valve condition in this manner eliminated the need to physically travel to field devices in favor of a comprehensive, online view of plant-wide diagnostics.

The combination of Hart technology with intelligent positioning control has reduced wear, extended service life and improved reliability of valves. In addition, the smart-communicating instruments provide better boiler control and more efficient steam production, according to Gordon, while remote monitoring of valve action through the DVCs creates substantial cost savings by identifying valves that are leaking steam or losing instrument air. And diagnostic support speeds troubleshooting to identify potential problems and provide an even, reliable supply of steam to downtown Milwaukee’s District Heating Steam System.

Decades of successive upgrades at Valley Power Plant lead Gordon to believe that “generally the technology pays for itself through improved operation and cost avoidance. In addition, they’ve found that the newer automated control systems work well, particularly when they receive accurate inputs from smart field devices.”  

Touching on one last technology that enhances diagnostics that will point technicians in the right direction, Larry O’Brien, the new marketing director for the Fieldbus Foundation in Austin, Texas, says, “The Foundation fieldbus Diagnostics Profile Specification (FF-912) was defined to allow any Electronic Device Description (EDD)-based system to access and configure the diagnostics in fieldbus devices. The field diagnostics profile makes no changes to the existing Foundation fieldbus stack specifications. However, the profile does introduce a new field diagnostic alert type. System updates will provide more extensive integration capabilities (such as Wizards for configuration) that will enhance diagnostics performance.”

Dan Roessler, Industry marketing, Aspen Technology (www.aspentech.com), sums up the situation, “When companies have a well-planned and effectively managed approach to asset management—established asset utilization metrics, display and distribution of asset utilization metrics to the right resources in user-friendly formats, and utilization of available analysis tools to quickly identify root causes and take corrective actions to resolve issues—they can improve asset efficiencies and realize profitability improvements.”

Aspen Technology (www.aspentech.com)
Avantis (http://iom.invensys.com/EN/Pages/Avantis.aspx)
Honeywell Process Solutions (www.honeywellprocess.com)
Hart Communication Foundation (www.hartcomm.org)
Invensys Operations Management (www.iom.invensys.com)
InControl Systems (www.incontrolsystems.com)
Rockwell Automation (www.rockwellautomation.com)

Gary Mintchell, [email protected], is Editor In Chief of Automation World.

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