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Management of Critical Settings (MCS)
Management of Critical Settings (MCS)
User Info…
19Dec06
V. Kain AB/OP
1
Introduction...
• Software to manage interlock thresholds which might need adjusting
during operation in a safe way…
In order to change a critical setting (interlock threshold)…
TrimEditor
RBA
Role based access: authentication + authorisation
If authorised: the new value is stored in the DB plus MCS digital signature.
LSA DB
If cycle resident: the new value is sent to the HW plus MCS digital signature.
CMW
FESA
FESA verifies the MCS digital signature.
If successful, new interlock threshold stored in HW.
Digital signature is generated from data set with a secret private key,
guarantees integrity of data.
19Dec06
V. Kain AB/OP
2
Scope (1)
•
The MCS should only handle key machine protection related interlock settings and parameters
–
•
restricted to only these machine elements
Interlock settings can be
–
–
–
single values
functions of time, energy, b*
tables (LHC BLM thresholds,…)
Equipment
comment
Movable protection devices and beam
cleaning collimators
• functions of energy and b* or time
Normal conducting magnet current
surveillance (ROCS)
• in the SPS and transfer lines
• normalized or absolute settings
• different settings resident in front-end for
different cycles
SPS extraction septa girder position
Kicker magnets
• charging voltage, kick delay, pulse length
• for extraction kicker (SPS), injection kicker
(LHC)
19Dec06
V. Kain AB/OP
3
Scope (2)
Equipment
comment
Beam Instrumentation
beam position at monitors BPCE418/618
bumped beam position in SPS extraction region
extraction region LSS4: different settings for
CNGS and LHC
beam excursion in IR6
orbit in LHC dumping region
beam life time in the LHC
fast BCT current change limit will be managed
by MCS
BLMs
• transfer line: interlock inhibits next extraction
• LHC: interlock settings depending on
integration time and energy. Management not
completely defined yet
RF
•
frequency offset limits in the LHC will be
managed by the MCS
The MCS will/could also be used to manage
–
–
–
19Dec06
reference values for beam dump XPOC
reference values for the Software Interlocking System
operating conditions during commissioning
V. Kain AB/OP
4
MCS & digital signatures…Info
•
Simplified picture:
–
•
MCS signs data with a private key and front-ends only accept data with the correct signature, verified with the public
key.
MCS Method
–
after the initialisation or modification of critical settings
• new signature is generated from data with private key AND stored with the data in the database
–
the data is sent to hardware from the database
–
FESA has the public key and verifies the signature
–
in case of correct signature data is transferred to front-end expert code otherwise rejected
–
front-end expert codes will stay untouched
19Dec06
V. Kain AB/OP
5