An intelligent filter control system using fuzzy logic for APS insertion device beamlines

A modular filter has been designed for the white‐beam undulator/wiggler beamlines at the Advanced Photon Source. For a typical hard x‐ray application, the filter assembly consists of four filter banks, and each bank has five beam apertures. Therefore a maximum of 625 filter combinations is mechanically possible. To prevent any mistaken setup, which could either damage the filter itself or downstream optical components, a programmable logic controller (PLC) based protection system has been designed. Fuzzy logic was used in this system to limit the memory size and improve the system performance. Ten different storage‐ring beam currents and ten insertion‐device gap setups have been chosen to cover a large dynamic operation range. Aspects of the system fuzzy logic design as well as an example of the calculated results for the control database are presented in this paper.