JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
@inproceedings{bousonville:linac2022-tupopa17,
author = {M. Bousonville and S. Choroba and T. Grevsmühl and S. Göller and A. Hauberg and T. Weinhausen},
title = {{Solving the USB Communication Problem of the High-Voltage Modulator Control System in the European XFEL}},
booktitle = {Proc. LINAC'22},
% booktitle = {Proc. 31st International Linear Accelerator Conference (LINAC'22)},
pages = {451--453},
eid = {TUPOPA17},
language = {english},
keywords = {controls, electron, interface, FEL, operation},
venue = {Liverpool, UK},
series = {International Linear Accelerator Conference},
number = {31},
publisher = {JACoW Publishing, Geneva, Switzerland},
month = {09},
year = {2022},
issn = {2226-0366},
isbn = {978-3-95450-215-8},
doi = {10.18429/JACoW-LINAC2022-TUPOPA17},
url = {https://jacow.org/linac2022/papers/tupopa17.pdf},
abstract = {{Since the commissioning of the modulators in the European XFEL in 2016, it happened from time to time that the modulator control system hung up. The reason for the problem was unknown at that time. Initially, the MTBF (Mean Time Between Failure) was 10⁴ days, which was so rare that other problems with the RF system clearly dominated and were addressed first. Over the next 2 years, the error became more frequent and occurred on average every 18 days. After the winter shutdown of the XFEL in 2020, the problem became absolutely dominant, with an MTBF of 2 days. Therefore, the fault was investigated with top priority and was finally identified. Two units of the control electronics communicate via USB 2.0 with the main server. Using special measurement technology, it was possible to prove that weak signal levels in the USB signal led to bit errors and thus to the crash of the control electronics. This article describes the troubleshooting process, how to measure the signal quality of USB signals and how the problem was solved in the end.}},
}