No one likes receiving those letters saying that your controls platform is so obsolete that its manufacturer will no longer be supporting it. When those letters arrive, it forces companies to ask, “What should we do about it? How do we migrate to a more up-to-date platform without ripping out wires and installing all new equipment?”The answer is to seek an automation vendor that advocates a migration strategy that matches your needs. In the case of a producer of petrochemicals, the right strategy was one that guaranteed continuity of operations. When management learned that support for its legacy Fisher Provox system would end in 2012, it decided to migrate to a new system at the very next planned shutdown in 2009. Waiting for the following one in 2012 would be too risky.Of the three proposals it considered, the company selected the one offered by Invensys Operations Management, headquartered in Plano, Texas. “We were able to retain all field wiring, input/output (I/O) cabinets, terminations and power supplies,” says the petrochemical producer’s control system manager. According to Invensys, this ability comes from the openness of its I/A Series distributed control system (DCS), its flexible mesh architecture and an I/O philosophy that permits a one-to-one replacement of other vendors’ I/O modules. The migration itself took place over four days, and checking the loops took another two weeks, all of which occurred during the month-long shutdown. The control-system manager attributes the success to seven months of planning beforehand and involving the right people from the start.Migration lessonsDan Tadie echoes this observation as he tells you about the seven successful migrations that he undertook at Colorado Springs Utilities, in central Colorado. A retired plant manager working part-time as a migration consultant under the name Sunhills Consulting, Tadie put these qualities at the center of the four-step migration plan that he developed during his 29-year tenure at the utility.The first six migrations converted pneumatic controls on six units in two plants to DCSs, but the last one at the Birdsall plant differed from the others in two important ways. First, this migration would retain most of the existing field devices. Second, it would replace the DCS with a platform based upon ControlLogix process automation controllers (PACs) from Milwaukee-based Rockwell Automation Inc.Birdsall’s three fossil-fuel-fired units had been sitting idle most of the time because long-term contracts allowed the utility to buy electricity cheaper than the plant could produce it. Whenever short-term economics favored using Birdsall, though, another plant would dispatch a crew to fire up the old Birdsall units for a while.Birdsall’s future came into question when the DCS manufacturer sent the utility the dreaded letter of obsolescence. An assessment, however, showed that a number of changes, including new controls, would allow the plant to continue contributing to the utility’s bottom line. “If Birdsall could be counted on to be reliable, it would offset power purchases of about $6 million a year,” explains Tadie.To avoid bringing yet another controls platform into the company, Tadie limited his search to the platforms already used there. Of the four that made sense at Birdsall, he chose ControlLogix. “Rockwell had an advantage with scalability,” he recalls. “I could operate our smallest hydroelectric site cost effectively and easily scale it up for our largest fossil-fired unit.”Four-step planThe first step in Tadie’s four-step migration plan was to identify the capabilities of his staff and to use them as much as possible. “We assessed what we could become capable of doing within the allotted time and budget, rather than what we were capable of doing right then,” he explains. “Everywhere we could, we used our in-house staff.”Because his staff consisted mainly of operators, he taught them the basics of instrumentation so they could execute the second step in his plan—identifying and verifying each control component in the plant, from field I/O to controls. At Birdsall, Tadie gave his staff a list of all known field devices and asked them to verify their calibration and to find any discrepancies. “They came up with two or three, which was great, because those would have been the ones that burned us at start-up,” he says.After you figure out where you are, the next step is to determine where you want to go, taking into account your budget and other constraints. Tadie recommends consulting an integrator for guidance if you do not have the resident expertise. He also urges having several conversations with the operators and technicians who interact with the units every day. “You may discover that a problem already written up a dozen times cannot be fixed because the controls don’t have the capability,” he says. “Be sure to build that capability into the new system.”The last step is to design the control solution. At Birdsall, Tadie left this to Rockwell Automation. “We provided alarm set points, the range and scaling of every field device, and field wire length so they could design the cabinets and termination locations,” he recalls. “But I wouldn’t allow them access to the original configuration.” The improvement was dramatic. “It was like driving a ’59 Buick for all these years and getting into a 2010 Camaro,” he reports. All three fossil-fuel-fired units can now come fully on line in 10 hours, rather than 12, and are more stable.Idemitsu Lubricants America Corp. had a similar experience when the ’90s-era controls at its blending facility in Jeffersonville, Ind., became obsolete. Not only was the vendor discontinuing support, but “we also had reached the limits of the tag database, which limited our expansion capability,” recalls Don Hartman, DCS and blending specialist at the manufacturer of automotive and industrial fluids.Like Colorado Springs Utilities, Idemitsu decided to take advantage of the situation and exploit new technology to make long-desired changes to recipe management, bulk-material handling, and final filling into drums and cans. Among those changes were converting the batch logic to modular ISA88 standards (from the International Society of Automation) and tweaking the controls and logic to increase efficiency, boost flexibility and streamline lot tracking.Idemitsu selected a Centum DCS from Yokogawa Corp. of America, of Sugar Land, Texas, the supplier of its old controls. “We could not afford a lengthy migration,” explains Hartman. “By staying with the same vendor that supplied our legacy system, we were able to migrate from our old system over the course of a three-day weekend with limited impact on production.”Another factor was the simulator built into the DCS. Yokogawa’s engineers used it to prepare a moderate-fidelity simulation of how the system would perform in Idemitsu’s blending process. The simulation reduced the testing time and gave Idemitsu the necessary assurance that the new system could be installed during the scheduled three-day shutdown.The installation was a success. Before the migration, more than half of the batches were set up and run manually. “Because our new system uses the ISA88 batch standard, it allows 100 percent automated operations, batch flexibility and recipe control,” says Hartman. He attributes the results to a detailed functional-requirements document that his company prepared at the beginning to identify the old system’s weaknesses and the desired improvements. It served as a reference manual throughout the project.Besides documenting a baseline and goal, another commonly overlooked element is the operators who will be using the new system. Not only can involving them early bring problems to light, as it did at Birdsall, but it also can be crucial in gaining their acceptance. The latter was important off the coast of Holland on the P6A natural gas platform owned by Wintershall, a subsidiary of BASF AG and Germany’s largest producer of crude oil and natural gas.When an obsolete human-machine interface (HMI) forced a change, management saw it as an opportunity to upgrade the platform’s legacy Bailey Infi90 system. They selected the Experion Process Knowledge System (PKS) from Phoenix-based Honeywell Process Solutions because the vendor uses an interface based on the OPC open connectivity standard to lay the Experion HMI over the old Bailey system. Honeywell’s engineers could also enrich process data collected by the controllers with advancements in alarm and other kinds of management.Operator buy-inThe team also had to get the operators to accept, learn, use and support the new interface. A quick buy-in by the operators was important because the migration had to occur within a year. The installation and commissioning, moreover, had to be done without any downtime, adds Hans Reijn, Wintershall’s facility engineer and project manager.For this reason, the migration team conducted a test-pilot phase to ensure that the operators liked the look and feel of the new HMI. The team built upon the familiarity that the operators had with other Honeywell products used on the platform. “Standardizing on one familiar interface gives our staff one less issue to worry about and makes them more productive,” notes Reijn.He reports that the new system went up without any interruptions in production. Technological progress is indeed great—when you manage it wisely to seek and seize the opportunities that come your way.Related Sidebar - In Defense of EvolutionTo read the article accompanying this story, go towww.automationworld.com/feature-7262.
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