ACS – THE ADVANCED CONTROL SYSTEM

The ACS is a CORBA-based control system framework with all features expected from a modern control system. It has been recently installed at the ANKA light source in Karlsruhe, Germany and is being used to develop the ALMA control system. ALMA is a joint project between astronomical organisations in Europe, USA and Japan and will consist of 64 12-meter sub-millimetre radio telescopes. ACS provides a powerful XML-based configuration database, synchronous and asynchronous communication, configurable monitors and alarms that automatically reconnect after a server crash, run-time name/location resolution, archiving, error system and logging system. Furthermore, ACS has built-in management, which allows centralized control over processes with commands such as start/stop/reload, send message, disconnect client, etc. and is fine-grained to the level of single devices. ACS comes with all necessary generic GUI applications and tools for management, display of logs and alarms and a generic object explorer, which discovers all CORBA objects, their attributes and commands at run-time and allows the user to invoke any command. A Visual configuration database editor is under development. An XML/XSLT generator creates an Abeans plug for each controlled object, giving access to all Abeans applications such as snapshot, table, GUI panels, and allowing one to use the CosyBeans GUI components for creating Java applications. For those that write their own control system, ACS allows to define own types of controlled data and own models of communication, yet use powerful support libraries as long as one adheres to some rules in the form of programming patterns. ACS users several standard CORBA services such as notification service, naming service, interface repository and implementation repository. ACS hides all details of the underlying mechanisms, which use many complex features of CORBA, queuing, asynchronous communication, thread pooling, life-cycle management, etc. Written in C++ and using the free ORB TAO, which is based on the operating system abstraction platfor