JSC ASC specialists have finished commissioning works in the framework of implementation of automated process control system, intended for strip cleaning prior to application of coating at Protective Coating Plant No.4 in PAO NLMK dynamo steel shop.
The system is designed to ensure:
- • operability of the unit in strip cleaning mode;
- • improved quality of application of coating to the strip by means of cleaning the strip immediately before the application of coating;
- • control and visualization of strip cleaning process;
- • collecting, storing and archiving of the critical process parameters of equipment performance;
- • accident prevention.
The control system is based on Siemens S7-1500 controller, which controls the transport mechanisms of a brush scrubber unit, the centering unit, the system of supplying water to a brush scrubber and steam to heaters, water heating-up in B12 tank and in tubular heat exchangers.
To receive signals from the control panel, sensors, actuating units, the cabinet containing the Odot IO-C distributed I/O station is installed.
For electric drives of strip transport rollers of a brush scrubber, the frequency converters of Inovance MD810 type are used to control the gear motors with built-in encoders and separately driven fans. For the rest of variable speed drives (of pumps, strip dryer fan, strip centering unit) the frequency converters of Inovance MD-500Plus type are used.
Direct control and monitoring of the area is performed via local control panel of a cleaner unit of a brush scrubber, equipped with Inovance IT7100E operator panel.
The entire unit is controlled via the main control panel, where the existing «thin client» of visualization system is installed. It has an Ethernet connection, through which it connects to the WinCC virtual station via a RDP-protocol, which makes it possible to remotely display the contents of its desktop. During the upgrade the new screens for displaying and controlling the strip cleaner’s process were added to the existing visualization system.
To ensure strip centering along the axis of the unit, Protective Coating Unit No.4 is equipped with a new centering mechanism, including a strip edge position sensor of a 2D-scanner type by Riftek.