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| THMBCMO24 |
Time Synchronization and Timestamping for the ESS Neutron Instruments |
1250 |
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- N. Holmberg, T. Brys, T. Bögershausen, M. Olsson, J.E. Petersson, A. Pettersson, T.S. Richter, F. Rojas
ESS, Lund, Sweden
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Funding: Tillväxtverket (Sweden) & European Union
The European Spallation Source (ESS) will be a cutting-edge research facility that uses neutrons to study the properties of materials. This paper presents the timestamping strategy employed in the neutron instruments of the ESS, to enable efficient data correlation across subsystems and between different sources of experiment data. ESS uses absolute timestamps for all data and a global source clock to synchronize and timestamp data at the lowest appropriate level from each subsystem. This way we control the impact of jitter, delays and latencies when transferring experiment data to the data storage. ESS utilizes three time synchronisation technologies. The Network Time Protocol (NTP) providing an expected accuracy of approximately 10 milliseconds, the Precision Time Protocol (PTP) delivering roughly 10 microsecond accuracy, and hardware timing using Microreseach Finland (MRF) Event Receivers (EVR) which can reach 10 nanoseconds of accuracy. Both NTP and PTP rely on network communication using common internet protocols, while the EVRs use physical input and output signals combined with timestamp latching in hardware. The selection of the timestamping technology for each device and subsystem is based on their timestamp accuracy requirements, available interfaces, and cost requirements. This paper describes the choice of method used for different device types, like neutron choppers, detectors or sample environment equipment and covers some details of the implementation and characterisation.
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Slides THMBCMO24 [0.384 MB]
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| DOI • |
reference for this paper
※ doi:10.18429/JACoW-ICALEPCS2023-THMBCMO24
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| About • |
Received ※ 06 October 2023 — Accepted ※ 11 December 2023 — Issued ※ 13 December 2023 |
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| THPDP052 |
Characterizing Motion Control Systems to Enable Accurate Continuous and Event-Based Scans |
1431 |
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- J.E. Petersson, T. Bögershausen, N. Holmberg, M. Olsson, T.S. Richter, F. Rojas
ESS, Lund, Sweden
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The European Spallation Source (ESS) is adopting innovative data acquisition and analysis methods using global timestamping for neutron scattering research. This study characterises the timing accuracy and reliability of the instrument control system by examining an integrated motion and fast detection system. We designed an experimental apparatus featuring a motion axis controlled by a Beckhoff programmable logic controller (PLC) using TwinCAT 3 software. The encoder readback is timestamped in the PLC, which is time-synchronised with the ESS master clock via a Microresearch Finland event receiver (EVR) using Precision Time Protocol (PTP). We repeatedly scanned the motor between known positions at different speeds. The system was characterised by correlating the position and timestamp recorded by the PLC with independent information using a fast optical position sensor read out directly by the MRF system. The findings of this study provide a good benchmark for the upcoming experiments in neutron scattering research at ESS and should be interesting for those aiming to build similar setups.
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Poster THPDP052 [1.185 MB]
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| DOI • |
reference for this paper
※ doi:10.18429/JACoW-ICALEPCS2023-THPDP052
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| About • |
Received ※ 05 October 2023 — Accepted ※ 08 December 2023 — Issued ※ 12 December 2023 |
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| Cite • |
reference for this paper using
※ BibTeX,
※ LaTeX,
※ Text/Word,
※ RIS,
※ EndNote (xml)
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