| Paper |
Title |
Page |
| MOPA03 |
Redundancy for EPICS IOCs
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26 |
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- L. R. Dalesio
SLAC, Menlo Park, California
- G. Liu, B. Schoeneburg, M. R. Clausen
DESY, Hamburg
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High availability is driving the reliability demands for today’s control systems. Commercial control systems are tackling these requirements by redundant implementations of major components. Design and implementation of redundant Input Output Controllers (IOCs) for EPICS will open new control regimes also for the EPICS collaboration. The origin of this development is the new XFEL project at DESY. The demands on the availability for the machine uptime are extremely high (99.8%) and can only be achieved if all the utility supplies are permanently available 24/7. This paper will describe the implementation of redundant EPICS IOCs at DESY that shall replace the existing redundant commercial systems for cryogenic controls. Special technical solutions are necessary to synchronize continuous control process databases (e.g., PID). Synchronization of sequence programs demands similar technical solutions. All of these update mechanisms must be supervised by a redundancy monitor task (RMT) that implements a hard-coded expert system that has to fulfill the essential failover criteria: A failover may only occur if the new state is providing more reliable operations than the current state.
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Slides
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| TPPA31 |
Redundant EPICS IOC in PC-based Unix-like Environment
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158 |
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- M. R. Clausen, G. Liu, B. Schoeneburg
DESY, Hamburg
- K. Furukawa
KEK, Ibaraki
- A. Kazakov
GUAS/AS, Ibaraki
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Redundant EPICS IOC is being actively developed at DESY in order to achieve high availability. Current development focuses on VME vxWorks environment for cryogenics controls. However, many facilities use PC-architecture and unix-like systems as Linux and FreeBSD. These facilities require high availability and redundancy as well. So this paper will describe the implementation of EPICS redundant IOC in PC-based environment with Linux and FreeBSD. This work will be done by porting Redundancy Monitor Task (RMT) and Continuous Control Executive (CCE). RMT is responsible to make a decision when to fail-over; it is rather independent and may be used in a wide range of applications. In the future it can be employed in caGateway to add redundancy. CCE is aimed to synchronize two RSRV-based IOC servers.
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