In a recent article published by Control Global, they took a look into three control types which have evolved to use more software and digital components, thus removing many of the functional obstacles, and allowing them to communicate more freely.
In past years, power distribution/conditioning and building management/automation systems (BMS/BAS) historically provided the energy and environment for production, while process control monitored and optimized operations as they happened. However, as all three control types evolved to use more software and digital components in recent years, they’ve also grown more similar in appearance and in how they’re applied.
Anchor Glass Container Corp. reports one of two old melting furnaces at its food-grade container plant in Shakopee, Minn., was causing energy inefficiencies, threatening productivity, and not allowing more than two weeks of production data to be viewed. The facility is one of six that takes crushed, recycled glass; chemicals and other raw materials, melts it at 2,700 °F, and produces about 600 bottles per minute, or about 300 million per year with about 18 changeovers per month.
The larger, 27 x 46-foot furnace is 17 years old, and needed to be re-bricked because its aging bricks provided poor insulation. This meant the furnace couldn’t maintain consistent temperatures, wasted energy, and risked producing lower-quality product. The glassmaker adds its furnace’s need for better thermal control was most evident in its reversal process, which relies on the regenerative furnace to maximize heat utilization. One side of the furnace captures heat; the process is reversed; and captured heat is reused by injecting it back into the furnace. Without tight control during this process, the furnace lost even more heat, and Anchor lost even more revenue.
In addition, the furnace’s old thermal monitoring system wasn’t user-friendly, required time-consuming manual adjustments and charting, and only stored two weeks of data. This lack of data visibility made monitoring and trending difficult, and prevented valuable analysis. Furnace operators also relied on an old, analog alarm system with only 12 alarms for the plant. To develop a new furnace control system, Anchor Glass worked with longtime collaborator Stone Technologies Inc., a CSIA-certified system integrator from Chesterfield, Mo., and they implemented a PlantPAx DCS from Rockwell Automation to monitor more than 1,000 tags and 2,600 alarms, which are tracked for frequency to improve predictive maintenance.
Historian software in the PlantPAx system also gathers data on furnace temperature, air pressure and other data points, which are viewable on an intuitive HMI with detailed sequencing that allows Anchor’s operators to fine-tune processes for more energy efficiency. PlantPAx also let Anchor Glass adopt more intuitive controls with consistent faceplates that require less training to operate, which was essential because only six staffers run the Shakopee plant.