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Follmann & Co has installed a highly-flexible plant for adhesives thatcan be reconfigured, expanded and relocated at any time using compactmodular controllers and HMI control terminals from Mitsubishi Electric
In process engineering programmable logic controllers (PLCs)are usually only deployed in sub-processes –higher-level tasks are handled by a central process control computer. The engineers at Follmann& Co have taken a different approach; they installed a highly-flexiblecooling, storage and filling plant for adhesives that be reconfigured, expanded and relocated at any time. Instead of an expensive centralised process control system, Follmann has used compact modular controllers and HMI control terminals from Mitsubishi Electric.
The Follmann Group manufactures chemical products for paper and textile finishing, including printing inks for paper napkins and wallpaper, PVC pastes for technical textiles, micro-encapsulated perfume and aroma oilsfor advertising, construction sealing systems and other specialised chemicals as well as adhesives for the wood and furniture industries.
Sales growth meant the existing cooling and storage tanks and the filling plant reached the limits of their capacity, so the company decided to expand the existing facility and to take the opportunity toautomate processes. The market for adhesives is so competitive that the company simply could not afford to shut down production. This meantthat the expansion and conversion project had to be completed while the plant remained in operation.
The control technology had to be expandable, flexible and failure-resistant, easy to operate and provide transparent visualisation of the processes. The management also wanted to have fast and reliable access to key process and production data.
After considering these specifications, the project team opted for an automation system controlled via a fieldbus for the product process paths, which run from the reaction tanks to the cooling andstorage tanks and the bottling plant.
The key question was, could the demanding control and process visualisation tasks required beperformed without a conventional centralised process control system. Follmann believed they could and selected a combination of compact programmable logic controllers and HMI control panels from Mitsubishi Electric to control the entire upgraded plant. Frequency inverter drives from the same manufacturer were chosen to operate all the pumps at theoptimum speeds.
The plant is divided into several control zones: A Melsec FX2N compact controller fitted with a full set of 256 inputs and outputs controls the reactor, the raw materials metering, the cooling system with the pigging line, the storage tanks and the fillingplant. Detailed information on the open and closed loop control processes are provided by graphical HMI control panels of the E series installed at the individual stations.
Frequency inverter drives ofthe compact FR S 500 series control the adhesive reactor’s metering pumps. The transport pumps for the storage tanks are controlled by inverters from the FR A 500 range. The objective here is to transport the products at maximum speed, making use of the available capacity of thepumps to guarantee rapid delivery.
With 600-1000 signals beingprocessed it was clear that a single compact controller was not goingto be able to handle this task on its own, hence the distributed design of the control system. This helped with another key requirement: that every system has to be quickly reconfigurable and expandable to cater to customer requirements.
PLC expansion and special functionmodules have been used to automated valve head selection at the container filling station. The local PLC uses an incremental rotary transducer to position a pneumatic cylinder.
The reactor controller has an Ethernet communications module that connects the PLC network tothe company’s office computer network, making it easy to exchange datawith the system and perform diagnostics and programming from any computer in the network. Follmann uses MX Sheet software to feed the process data from the PLCs directly into the existing office software.
The company is continuing its expansion, with more components and function constantly being added to the control system, including an automated tanker truck filling system.
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