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DEW Witten – Modernization of the S5 control system

Changeover from S5 to SPEED7 in less than an hour

Existing control technology at the limit of its performance

Die Deutschen Edelstahlwerke GmbH, a leading manufacturer of specialty steel long products and one of the largest tool steel manufacturer is considered to be one of the most advanced companies in the industry, demonstrated among other things, by being presented with the German Environmental Award. Especially here, where several ton blocks are brought into shape with massive rollers in furnaces of more than 1000 ° C,  energy efficiency plays a crucial role. Since in these ovens not only the flow of material is to be regulated, but the furnace parameters such as gas or air consumption are to be monitored and controlled, the previously installed S5 controllers increasingly reached their limits. The connection of the control systems in higher-order systems such as an energy controlling with the existing hardware by simple means was no longer possible. Also special quality requirements, as required by customers in the aviation and aerospace industry, could not be fulfilled without the modernization of control technology.   

Gradual modernization

With the VIPA IM 306 interface modules, the solution was found in which it was possible to exchange the S5 CPU alone without exchanging the whole system controller. Together with the SPEED7 CPU 315SN/NET from VIPA, the old S5 controller transformed into an S7 controller that could now easily communicate via Ethernet with the higher-level systems and fulfilled all the requirements regarding cycle time and memory size. The S5-E/A components were able to remain in place, also the wiring of the signal modules could be retained. According to Ibrahim Agpolat, the person responsible for process technology in Witten, the conversion itself lasted less than an hour. Since most of the S5 spare parts, no longer manufactured, are still in stock at DEW, there was enough time for the conversion of the peripherals to newer systems.

SPEED7 standard moves slowly into all production areas

This good experience led DEW to use the time during planned shutdowns of plant parts in order to convert the control systems to the new technology completely, a move which has already been done in some of the furnaces. The continuous conversion of the technology that is carried out, however, with no great time pressure and also within budget suits the intentions of DEW very well.