2003
-
Knoxville, TN - USA
Control system upgrade for 500,000 ton/yr bar mill
Russula upgraded the electrical and control system for the 500,000 tpy bar mill in Knoxville, TN, USA for CMC Texas (formerly Gerdau). The entire upgrade was commissioned in just a little over 11 days.
Scope of Supply
The projects consisted of a new control system, operator’s desks, HMI as well as modernizing AC and DC drives for their 500,000 ton/yr bar rolling mill. Also included in the scope were engineering, project management, commissioning, support and training.
- ABB AC800M PLC
- ABB DCS600 drives
- ABB ACS600 drives
- Rockwell RSView HMI
Drive lineup
Control shear desk
Project Execution
Russula implemented the rolling mill control automation in standard IEEE 61131 programming language using standard ABB AC800M Modular Controllers. A high speed data acquisition system along with networked drives and controller software provided single point monitoring and diagnostics to the upgraded systems.
Sixteen existing ASEA mill stand drives were upgraded to fully digital control using the existing thyristors, along with complete new digital field supplies. The upgrades were pre-engineered, assembled, and tested on steel panels which were installed in the existing drive cubicles and commissioned during normal operations with no additional downtime.
Results
After the electrical modernization in 2002, Gerdau Knoxville plant noticed a marked improvement in the operation of the rolling mill process, which yielded increases in production especially because of less cobbles.
The plant was able to concentrate more on operational improvements, rather than consuming valuable engineering and maintenance resources with obsolete electrical equipment. This change in focus from “fighting fires” to “preventing fires” is one of the reasons for their continued success.
Between the years 2003-2005, the yearly average of ”billets between cobbles” more than tripled from 321 to 975. Less cobbles were produced as a result of more accurate speed and cascade control which equated to more consistent operation and less downtime.
