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This article illustrates the project-designer's approach to rolling mill automation by considering two very different recent examples; a 2-strand rod mill installation and a plate mill complete with plate finishing facilities. The installations are described in general terms, with particular attention paid to the control aspects.
GEC Electrical Projects Ltd specialises in planning and handling comprehensive electrical projects. These generally include design and supply of electrical power distribution systems, process drives and control and automation of the process (which itself may include automated production control as well as specific process control), together with installation and commissioning on site.
The control of any process, and a rolling mill is no exception, comprises two main factors:
1. General production control aspects of the business, involving for example customer order inputs, stock control of work in progress, and keeping various records or logs of achievement in terms of quantity and quality.
2. Specific control of the process to achieve the aims which are set by the production requirements.
The automation requirements of a process can be expressed under a hierarchy of command control comprising four levels of hardware and software. These cover areas such as: works planning; production coordination; dynamic on-line data handling and processing; and finally control of the process itself, with equipment such as GEC's GEM 80 microcontroller.
The following descriptions of two types of mill illustrate GEC's approach to control system design.
The 2-strand Rod Mill for Sonasid in Morocco demonstrates GEC's application of distributed process control via microprocessors - in particular the benefits which the GEM80 microprocessors bring to the plant operators with their powerful semi-graphic facilities.
In general the more complex the process, with many possible routes for transfer of stock from one location to another and differing residence times in the stock holding areas, the greater will be the benefits from applying automation to production control. This is apparent in the description of GEC's control system for the plate and plate finishing mill complex at Sicartsa in Mexico.
Sonasid 2-strand rod mill
The 2-strand rod mill built by Davy McKee (Sheffield) Ltd and completed in 1984 at SO. NA. SID's Nador Works in Morocco was designed as the first stage of a greenfield site steel complex development.
The mill is a...