The control system provides the man-machine interface of the accelerator facility. It enables an easy to survey and reliable operation of the facility, a clear graphical representation of the machine parameters and of their time behaviour for the operator and makes the machine parameters available for technical and physical calculations. In addition, the system keeps the data sets for different machine parameter adjustments ready, stores and files the time dependence of the measured values for later evaluations.
For these tasks of process visualization and handling, the system WinCC (Windows Control Center) from SIEMENS will be used as a coordinated multi-user system with a WinCC server and several WinCC clients on the base of PC's under the Microsoft Windows 2000 operating system.
The figure shows the basic structure of the control system of the Radiation Source ELBE.
The WinCC server communicates via the PROFIBUS-FMS with the process layer and drives the management of the process data. The data exchange between the operator stations and the accelerator equipment is running via the WinCC server, which realizes also the archiving of the process data as well as performs global tasks in the entire project. The manipulation occurs via the clients in the control room and - in a restricted manner - in the experimental areas. The reliability with regard to access and operating permissions is guaranteed by the WinCC and the operating system of the PC's, respectively.
A lower process layer realizes the connection between the operator level and the components of the equipment concerned and operates largely autonomously. For this purpose, programmable logic control units (PLC) of SIEMENS are generally used in form of a distributed system with SIMATIC S7 and error-tolerant SIMATIC S5 (for the interlock system), respectively. They serve the aquisition of analogous input data, as currents, voltages, pressures, dose rates etc., as well as the output of analogous values to be included into the process. In parallel with this, a large number of binary values can be read in (status) and out (commands). In addition, also logical operations, interlocks, monitoring and control are realized at this hardware-based level.
For networking the profibus is applied together with fibre optics as transmitting medium in order to guarantee a potential isolation and an optimum of surge and transmission protections. On the process layer, the profibus is used with the protocol DP (non-central periphery), whereas using of the protocol FMS (feldbus message specification) is preferred at the higher layer. The interconnection between the computers of the operator level is realized via ethernet.
The signal acquisition of the measuring devices for beam diagnostics is organized with data acquisition boards resp. frame grabbers (for recording and analysing the view-screen displays) under Labwindows/Labview by National Instruments.