An integrated control and supervision system (“ICOSS”), which represents a new approach to the control and supervision of processing units, has been implemented in a Shell refinery. The major aims of ICOSS are: centralization of control equipment in a relatively small area, provision of well-dosed, digested information for the operator and easy implementation of modern control techniques. The system is based on two digital computers and an in-house developed controller system designed for easy communications with the computers so that the implementation of direct digital control and set-point control is facilitated and adequate back-up is provided. The controller system is remotely onerated from a centralized console and back-up is fully integrated in the sense that the panel operator uses the same buttons and displays regardless of whether control resides in the computer, in the controller system or is shared between them.
