Case Study: Comsteel Bar Mill Upgrade

Scope: Design, manufacture, install and commission a replacement control and drive system to increase the reliability and flexibility of the mill, using standard automation products.

A Siemens S7 400 PLC and Simadyn control card were selected to perform the speed reference, tension & looper control functions. Simadyn T400 stand-alone control cards were selected for speed and position control of the two shears. Both Simadyn products provided high-density encoder inputs, digital & analogue I/O. The cards performed high speed, high precision dynamic control using standard graphical blocks from the Continuous Function Chart (CFC) software library.

A system comprising new SCADA workstations, industrial Ethernet, the S7-400 PLC, the Shear T400s, the existing S5 PLCs and Profibus was set up in parallel with the operating system. All of the control fundamentals were pre-tested and proven prior to commissioning. The control functions were gradually migrated from the original to the new system. This staged approach enabled Comsteel to participate and witness the performance of the new controls. Scheduled mill down-days were used for pre-commissioning and installation in order to minimise downtime. The existing I/O, panels, and field cabling were retained, representing a major cost saving and minimising the risk of production delays during changeover.

Client: Client: Smorgon Comsteel

Hot roll mill