CICERO: developing complex distributed control systems using object technology

Modem High Energy Physics (HEP) experiment and accelerators in nuclear physics at the CERN laboratories in Geneva require sophisticated control and management systems to ensure their safe operation and performance. All management activities related to the acquisition, supervision and operation of the experiment or accelerator are part of the control information system. It gathers slowly changing parameter information which is used for experimental set-up safety, system calibration, system configuration and operational maintenance of low level automation loops. These control information systems are a non-negligible part of an HEP experiment and are estimated to be about 10% of the cost of the data acquisition system. The increased number of sensors required (about 96000 in the present DELPHI experiment), together with the complexity of sensor and instrument subsystems in many cases with their own local management systems have forced physicists and engineers to reconsider the organisation of HEP experiments. The wide physical distribution and heterogeneity of both control and management subsystems has led to a situation where integration and communication between these components has become an issue. The operation of these distributed control systems has highlighted a contradiction: on the one hand a lot of sensors are needed to improve reliability, and an the other, the induced complexity makes the system difficult to operate, upgrade and maintain and thus less reliable. Consequently a substantial amount of manpower and many experts are needed even for basic interventions, since the overall view of the experimental state is difficult to grasp for the physicists and operators on shift. It is predicted that the next generation of experiments being constructed for the Large Hadron Collider will increase the complexity by an order of magnitude. The CERN Research and Development project (RD-38), named CICERO, aims to identify and design the main building blocks of a generic control information system based on distributed objects. The project is producing an integrating framework (named Cortex) into which user real-time control objects will be plugged (and played) and a control information system to support its configuration and management. Development of Cortex is following the ESA PSS-05-02 software engineering standards. An overview of the CICERO project follows and then the remaining part of the paper concentrates on Cortex which provides the collaborative infrastructure for distributed components