Optima Control Solutions

The Polytype control systems were becoming increasingly unreliable and unable to meet the production output that was required. It was essential to have a reliable and cost effective solution to meet the ever-increasing production demand.

Optima carried out assessments of the options available for the end users, and concluded that the most economical solution would be to completely upgrade the machine control systems, but to retain the existing DC motors. These had been well maintained and had years of useful life ahead.

The decision to retain these motors considerably reduced the project cost and has been justified by the improvement of the web tension throughout the machines.

To ensure that there was minimum disruption to production output, the new control system was installed and commissioned during the Christmas shutdown. It was essential that the changeover from the old control system to the new be achieved within the agreed timescale.

The following elements, within the control system design, enabled the specified start-up date to be achieved.

· The electrical installation time was kept to a minimum by retaining the original power cables and replacing the multitude of control cables with a distributed PLC system. Over 80% of the original control cables were removed.

· The distributed PLC system consisted of both conventional and ATEX certified remote I/O units. The ATEX remote I/O units allowed the safe connectivity of the new coating station operator control panels, located in a Zone 1 area, to the main PLC. The use of a distributed I/O system allowed the control system to be thoroughly tested before installation on site, resulting in a reduction in commissioning time.

· The DC drive controllers were connected to the PLC via a communications network. All of the drive functionality and operator interfaces could be thoroughly tested before installation and commissioning of the system. This also kept the commissioning time to a minimum.

In any highly competitive market, increased demand for products usually means that quality is lost due to increased line speeds. However, for these end users, the reverse is true, as modest investment in new control technology has resulted in improved reliability, production capacity and quality.