Author: Vaga, F.
Paper Title Page
WEC3O01 Trigger and RF Distribution Using White Rabbit 1
 
  • T. Włostowski, G. Daniluk, M.M. Lipinski, J. Serrano
    CERN, Geneva, Switzerland
  • F. Vaga
    University of Pavia, Pavia, Italy
 
  White Rabbit is an extension of Ethernet which allows remote synchronization of nodes with jitters of around 10ps. The technology can be used for a variety of purposes. This paper presents a fixed-latency trigger distribution system for the study of instabilities in the LHC. Fixed latency is achieved by precisely time-stamping incoming triggers, notifying other nodes via an Ethernet broadcast containing these time stamps and having these nodes produce pulses at well-defined time offsets. The same system is used to distribute the 89us LHC revolution tick. This paper also describes current efforts for distributing multiple RF signals over a WR network, using a Distributed DDS paradigm.  
slides icon Slides WEC3O01 [1.460 MB]  
 
WEPGF062 Processing High-Bandwidth Bunch-by-Bunch Observation Data from the RF and Transverse Damper Systems of the LHC 1
 
  • M. Ojeda Sandonís, P. Baudrenghien, A.C. Butterworth, J. Galindo, W. Höfle, T.E. Levens, J.C. Molendijk, D. Valuch
    CERN, Geneva, Switzerland
  • F. Vaga
    University of Pavia, Pavia, Italy
 
  The radiofrequency and transverse damper feedback systems of the Large Hadron Collider digitize beam phase and position measurements at the bunch repetition rate of 40 MHz. Embedded memory buffers allow a few milliseconds of full rate bunch-by-bunch data to be retrieved over the VME bus for diagnostic purposes, but experience during LHC Run I has shown that for beam studies much longer data records are desirable. A new "observation box" diagnostic system is being developed which parasitically captures data streamed directly out of the feedback hardware into a Linux server through an optical fiber link, and permits processing and buffering of full rate data for around one minute. The system will be connected to an LHC-wide trigger network for detection of beam instabilities, which allows efficient capture of signals from the onset of beam instability events. The data will be made available for analysis by client applications through interfaces which are exposed as standard equipment devices within CERN's controls framework. It is also foreseen to perform online Fourier analysis of transverse position data inside the observation box using GPUs with the aim of extracting betatron tune signals.  
poster icon Poster WEPGF062 [4.408 MB]  
 
THHA2I01 Developing Distributed Hard-Real Time Software Systems Using FPGAs and Soft Cores 1
 
  • T. Włostowski, J. Serrano
    CERN, Geneva, Switzerland
  • F. Vaga
    University of Pavia, Pavia, Italy
 
  Hard real-time systems guarantee by design that no deadline is ever missed. In a distributed environment such as particle accelerators, there is often the extra requirement of having diverse real-time systems synchronize to each other. Implementations on top of general-purpose multi-tasking operating systems such as Linux generally suffer from lack of full control of the platform. On the other hand, solutions based on logic inside FPGAs can result in long development cycles. A mid-way approach is presented which allows fast software development yet guarantees full control of the timing of the execution. The solution involves using soft cores inside FPGAs, running single tasks without interrupts and without an operating system underneath. Two CERN developments are presented, both based on a unique free and open source HDL core comprising a parameterizable number of CPUs, logic to synchronize them and message queues to communicate with the local host and with remote systems. This development environment is being offered as a service to fill the gap between Linux-based solutions and full-hardware implementations.  
slides icon Slides THHA2I01 [2.525 MB]