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| Meeting held on June 31, 2001 |
P. Gayet, L. Serio, M. Sanmarti, M. Lamont, A. Butterworth |
Green Light
The CCR will give the green light for powering after a cooldown of the machine, after the cooldown of a sector, after recovery from quench. This green light will be based on predefined powering zones.
In turn the vacuum group/system will give a green light for cooldown based on the state of the insulation vacuum.
Some discussion about what the cryogenics system will do in the event that the green light conditions are not met during operation with beam. Four conditions normally to be met are:
What could go wrong?
In the case of a temperature rise above 2 K an alarm will be raised, whether a power abort by the cryogenics system is made is open to question. If no abort is made eventually a quench may occur. One will have to weigh up the cost of an abort versus the cost of a quench recovery.
Generated in SCADA. Clearly alarm subsets for PCR and CCR and TCR.
From machine to cryogenics
Use for predictive control, important to deal with sudden changes in heat load, such as that experienced by the inner triplets during the squeeze (is pre-warning required?).. Frequency around 1 Hz, would view subscribing to this information via the middleware. The data would be accessed by the PLCs NOT via the SCADA. (PLC to Ethernet to OPC server to middleware). Data includes:
From cryogenics to PCR
Foresee dedicated workstation in PCR where PVSS applications would should standard trends, and estimates etc. Any low level data transfer required?
From cryogenics to vacuum
Both systems are using PVSS - data exchange (pressures, interlocks etc.) should not be a problem. Alarms and logging should (could?) be a common solution.
No long term logging provided by cryogenics system. Will keep data for 30 days for use by cryogenics operations, extraction will be required to central logging repository. Rates need to be discussed further.
Timestamping
Standard solution providing GPS at PLC level foreseen.
Monitoring will be performed at 2 Hz. Storage not as yet planned for these data - cryo problem.
The following word documents are a first stab performed in 2000:
Other suggestions
Naming, controls support, fault recovery - logistics.