Finite State Machine implementation to automate RF operation at the TESLA Test Facility

At DESY the Distributed Object Oriented Control System (DOOCS) was developed to solve a variety of control tasks at the TESLA Test Facility (TTF) Linac. DOOCS is designed from the device server level, to control different parts of the hardware, up to the console, where it provides a graphical user interface (GUI) to the operators. The Finite State Machine (FSM) concept has been integrated into DOOCS to simplify the automation of the accelerator operation. This paper describes the FSM server implementation for automated RF operation at the TTF. The server consists of two main elements-the control manager and a tools section. The control manager is responsible for RF field control. The start up, restart and routine operation of a 10 MW klystron, that currently powers 16 superconducting cavities, is successfully controlled by a DOOCS FSM server. The FSM process includes loop phase measurement and correction, feedforward and feedback parameter adjustments, beam loading compensation, calibrations, and automatic fault recovery. A variety of automated procedures are available in the tools section, which assist the operators in maximizing the performance of the RF system