| Paper |
Title |
Page |
| MOD005 |
Evolution of the EPICS Channel Access Protocol
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40 |
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- K. Zagar, M. Sekoranja
Cosylab, Ljubljana
- L. R. Dalesio
BNL, Upton, Long Island, New York
- M. R. Kraimer
ANL, Argonne
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Experimental Physics and Industrial Control System (EPICS) is one of the most widely deployed control system infrastructures in large experimental physics community. At EPICS' foundation are 1) the real-time process database, which allows integrators to build the control system from reusable building blocks (e.g., device drivers) into a coherent whole without much coding or other kind of development, and 2) the Channel Access protocol, which allows the database to be distributed across several computers in a scalable way. In this contribution, we describe the objectives of the next major EPICS release (v4). In particular, we focus on the improvements of the Channel Access protocol that will allow it to support additional functionality, such as structured process variable data (pvData) and client-specified filters. We also describe how this functionality is implemented while simultaneously further improving the Channel Access' performance (no-copy get, flow control improvements, beacon traffic reduction, zero-length queues, etc.). We also discuss potential for future improvements, such as use of IP multicast and a layer for implementing remote-procedure call style of communication.
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Slides
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| TUP104 |
NSLS II Control System
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319 |
| |
- L. R. Dalesio, G. Carcassi, D. Dohan, N. Malitsky, G. B. Shen, Y. Tian
BNL, Upton, Long Island, New York
- L. R. Doolittle, A. Ratti
LBNL, Berkeley, California
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Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U. S. Department of Energy.
The NSLS II is a new third generation light source. The project is pushing control system technology in three areas: fast orbit feedback, use of RDB technology, and model based control architecture. This paper describes these developments in terms of the overall control system architecture.
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| WEB005 |
Power Supply Control System of NSLS-II
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385 |
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- Y. Tian, L. R. Dalesio, G. Ganetis, W. Louie, J. Riciardelli
BNL, Upton, Long Island, New York
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A novel architecture in power supply control system at NSLS-II is discussed. The architecture provides a synchronous, deterministic and fault tolerant communication protocol for power supply control system. The architecture is designed to be able to achieve NSLS-II power supply control tasks. It also fits well into the general architecture of fast orbit feedback system and slow orbit feedback system. At NSLS-II, all the power supplies (including dipole magnet power supplies, multipole magnet power supplies and corrector magnets power supplies) will be controlled using this same architecture.
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| THP036 |
A Proposal for Introspection In EPICS
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739 |
| |
- L. R. Dalesio, D. Dohan
BNL, Upton, Long Island, New York
- R. Lange
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin
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Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U. S. Department of Energy.
Introspection provides some mapping of function to process variables. To implement this in EPICS, a service is required to define these relationships that may be accomplished external to the control system as an extension to the directory service. This paper outlines the functionality and design to implement this functionality.
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| THP061 |
NSLS-II Insertion Device Controls Plan
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776 |
| |
- T. Tanabe, D. Chabot, O. V. Chubar, L. R. Dalesio, D. A. Harder, J. Rank
BNL, Upton, Long Island, New York
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Controls on insertion devices usually comprise of motor controls, encoders, cooling water for in-vacuum devices, various sensors such as limit switches and temperature sensors. Interlocks are provided independently from the device controls. They have been considered "slow" control elements and very little attentions have been paid to the response and latency of ID controls. However, current project scope of NSLS-II project demands very tight tolerance of beam movement of submicron level. More frequent use of elliptically polarizing undulators (EPUs) also requires synchronized movement between gap and phase motions to ensure the stability. Furthermore, future demand for synchronization of ID state and beamline components prompt more sophisticated schemes. Synchronous Device Interface (SDI) is originally proposed for fast feedback I/O interface and integration of some ID controls to SDI is considered as well as other options.
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Poster
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| THP090 |
Advanced Monitor/Subscription Mechanisms for EPICS
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847 |
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- R. Lange
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Elektronen-Speicherring BESSY II, Berlin
- L. R. Dalesio
BNL, Upton, Long Island, New York
- A. N. Johnson
ANL, Argonne
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Funding: Work supported by U. S. Department of Energy (contracts DE-AC02-06CH11357 resp. DE-AC02-98CH10886), German Bundesministerium für Bildung und Forschung and Land Berlin.
Publish/subscribe systems need to handle the possibility that there are subscribers requiring notification at an update rate much lower than the publisher's natural frequency, or synchronized to external events. Feedback or pulse-to-pulse diagnostics are processed at rates in the 100Hz or even multi kHz range, while many subscribers will not be able to process the data at this rate: e.g. archiving, visualization, and processing clients each require specific, different update rates. Sending more updates than required wastes processor and network bandwidth. A subscriber should be able to specify rate limiting factors or filters that are instantiated and guaranteed by the publisher. Many accelerators, especially pulsed machines, are using a hardware event system to distribute fiducials and events from a central event and/or frequency generator. These events should be integrated into the publish/subscribe system to support posting event synchronous updates to subscribers that require synchronized data. This paper investigates several approaches to provide these functionalities in the EPICS architecture.
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