The Deutscher Elektronen-Synchrotron DESY, a national research center in Germany which operates particle accelerators used to investigate the structure of matter, has relied on PROFIBUS DP and PA for many years to control and monitor its control and instrumentation systems. Particular challenging are the cryogenic systems where superfluid helium II cools the cavity resonators and magnets down to 2 degrees Kelvin. The cryogenic system is currently being converted for the new XFEL (European X-ray Free-Electron Laser) accelerator and its test facility AMTF (Accelerator Module Test Facility).
The XFEL will operate 24/7 and be controlled via EPICS (Experimental Physics and Industrial Control System), which communicates with its I/O via PROFIBUS DP. Valves, pressure transmitters and flow transmitters are networked with PROFIBUS PA. All parts of the system are connected to the control system via Ethernet. Components such as the power supply and segment coupler, the optical link module and fiber optics (double ring) are redundant. The physical layer is self-monitoring.
The use of PROFIBUS DP and PA has proven itself in many ways: simple system planning without the use of special tools; straightforward documentation; and simple installation and commissioning. A further benefit is the diagnostic capabilities, which assist in early fault finding to ensure maximum availability.
Contributed by Pepperl+Fuchs