With 80,000 employees and operations in 70 countries around the world, Holcim has an understandable need for standards. The Switzerland-based company is a global leader in the production of cement, aggregates, concrete and asphalt, and its internal standards apply to how its many production facilities are automated, even how often those controls should be evaluated for upgrade. Several years ago, the 1980s-era controls at its Macuspana cement plant in Tabasco, Mexico, were deemed to have reached the end of their useful life, according to Fernando Hernandez, automation and control supervisor. "We needed to migrate to a new generation system that would be faster to react and control."
And while the need to modernize was first acknowledged in 2007, the global economic downturn delayed action until 2012, when the plant embarked on an 18-month, phased effort to bring the plant's aging infrastructure up to speed, modernizing older PLC-5 and RSView visualization software to PlantPAx technology from Rockwell Automation. Hernandez described his company's journey in a presentation today at the Rockwell Automation Process Solutions User Group (PSUG) meeting held in Anaheim, California, during the run up to Automation Fair 2014.
Before the migration, the plant's automation architecture consisted of PLC-5 controllers linked to remote input/output racks via Remote I/O (RIO) protocol. ControlNet was used for peer-to-peer controller communications as well as for integration with supervisory level systems. The slow speed of the RIO networks in particular had begun to hamstring operations, Hernandez said. In the new architecture, ControlLogix controllers have replaced the PLC-5s; ControlNet has replaced RIO; and EtherNet/IP is used for integration with higher level systems.
EtherNet/IP might have been used throughout, Hernandez added, but corporate standards again came into play. In particular, ControlNet had been approved for implementing the peer-to-peer interlocks among process units and should be adequate for the plant's near-term needs. "That may change in a year or two," he said. Hernandez also noted that the PlantPAx system's library approach to control logic and visualization templates worked particularly well with Holcim's corporate standards for common cement manufacturing operations.
The new system already has begun to pay off. "With the new HMI control system and diagnostic tools, the plant is having fewer unplanned stoppages," Hernandez said. "The new platform also provides more diagnostic tools in case of failure and lower maintenance costs, and it will result in a higher level of competitiveness for the company." In the future, the plant plans to tap the as yet unexploited power of the new control processors to achieve better power and thermal control, Hernandez said.
With its new controls in place, plans are in the works to share the plant's modernization experience with operating units around the globe, for example, in Australia and South America where PLC-5s are still in use. The Mascuspana plant has set a new standard for Holcim, "a success that we'll now take to plants in other countries," Hernandez said.