Hand-shake Signals Between LHC Machine and Experiments Mike Lamont Thanks to Daniela Macina for her input

Communication GMT BST DIP events, telegrams, time of day, safe machine parameters BST DIP publish/subscribe a very loose coupling 10/03/2008 Handshakes

Modes Accelerator Beam Operational 10/03/2008 Handshakes

Beam Modes 10/03/2008 Handshakes

Injection & Transfer No Beam 10/03/2008 Handshakes

Proposal – publish values in DIP LHC_READY_FOR_INJECTION none, prepare, imminent, injection ATLAS_READY_FOR_INJECTION no injection, prepare, ready for beam Flags monitored by Software Interlock System injection inhibit if all experiments not equal ready 10/03/2008 Handshakes

Proposal LHC publishes “Injection Imminent” Need to know that expt has got the message Experiment publishes “preparing” with 10 seconds, say. If it doesn’t it gets a phone call LHC continues preparation when ready checks and/or waits for all expts “ready” - phone call possible When all expts ready, switch mode and ramp to injection level 10/03/2008 Handshakes

DIP 10/03/2008 Handshakes

Imminent injection the experiments are ultimately protected by the “injection inhibit signal”. an “imminent injection” warning signal would give time to the experiment to put the detector in stand-by mode therefore allowing injection into the machine “in time”. The optimal delay between the warning signal and injection would be minutes The switch from SETUP to INJECT PROBE will be made less than a minute before the machine would like to inject (eventually). Thus the “injection imminent” flag would be set in one of the SETUP sub-phases (this can be tuned). 10/03/2008 Handshakes

Physics 10/03/2008 Handshakes

Stable beam to Adjust LHC_TO_ADJUST ATLAS_READY_FOR_ADJUST None, prepare, ready, OK ATLAS_READY_FOR_ADJUST None, prepare, ready Going to have to go on trust here, rely on sequencer, hard to imagine imposing an inhibit 10/03/2008 Handshakes

Scheduled Beam Dump LHC_READY_FOR_BEAMDUMP ATLAS_READY_FOR_BEAMDUMP none, prepare, imminent, OK ATLAS_READY_FOR_BEAMDUMP none, prepare, ready Going to have to go on trust here, rely on sequencer, cannot impose an inhibit 10/03/2008 Handshakes

Suggest we suck it and see – dry runs incoming DIP - comments Pub/Sub not ideal never know who’s subscribing and whether or not intended recipient has got the message with these asynchronous messages, subscriber doesn’t know if the publisher is alive and kicking no persistency no message logging What we have is an attempt to do a loose command/response possible two-way heartbeats during the relevant modes Suggest we suck it and see – dry runs incoming 10/03/2008 Handshakes

Dry Runs 10/03/2008 Handshakes

Physics/Experiments Dry Run Luminosity Acquisition and display, BRA application Optimization, trims, bumps etc. Scans Experiment Instrumentation & signals BCMs, Lumi etc. Experiment communication DIP – to & from Vetos, Handshakes Interlocks Beam abort, injection inhibit Magnets Alice/LHC dipoles and compensation 10/03/2008 Handshakes