Digital control of the LEP RF system

The RF system for the initial phase of LEP consists of eight identical units of 16 cavity assemblies with associated high power and control equipment. These units are installed underground, distant from the control center, and each one has around 2,500 parameters and status indications, all of which must be remotely accessible. Digital control is achieved by assigning a G64 based equipment controller crate to each major element of the unit linked by a bus to a VME based data manager with overall control and connection to the control network. It executes locally or remotely initiated complex control and surveillance procedures to simplify operation. The different classes of parameter and data are summarized. Interfacing and control within the equipment controllers and communication with the data manager are outlined. The form of equipment access functions and the development of complex control procedures are discussed. The implementation of corresponding functions at control console level is discussed. Finally experience with the six RF units presently installed is described. 4 refs., 3 figs