Post Mortem procedure for DCS shifters

  • The diagram below presents the BCM system logic (upper lane) and shifter's action (lower lane) after Post Mortem occurs:


Reminder of some BCM & Post Mortem procedures for DCS Shifters:

A. There are several situations when status of the ALICE permits may change:

  • LHC injection handshake,
  • CCC (via Shift Leader) asks for giving the permits manually,
  • Post Mortem
  • arming of the Beam Permit after Post Mortem triggered by ALICE
  • manual removing of the injection permits on Shift Leader request

Shifter should verify then on the alarm screen if there is no alarm related to lhc_exchange project. There are 2 obsolete alarms from lhc_exchange: FSM summary (from 2008 and 2009) - do not worry about them.

By default the manual rearming of the injection permits can be performed only if ALICE is SAFE and CCC expects them. For some LHC tests when the injection is not planned the permits might be armed irrespective of the SAFE/SUPERSAFE state (only on Shift Leader request!).

B. In case of communication problems (alarms, problem with giving the permits) the shifter can:

  • 1. Give the permits using emergency button if CCC is expecting them (TWIKI, FOLDER)
  • 2. Try to restore the communication using recovery button (DCS GUIDE, FOLDER)
  • 3. Check what is the true status of permits/transient recorder using manual report (on the panel ali_dcs\lhc\dcs_bcm\bcm_tell1) - upon Oncall request

DCS On call should be immediately informed.


Post Mortem:

  • can occur anytime
  • it implicates the injection permits are removed automatically
  • if ALICE BCM caused the beam dump then also the Beam Permit is removed
  • Post Mortem last ~ 3 minutes

After the Post Mortem the shifter should check:

  • if permits were rearmed if necessary (i.e. ALICE is SAFE and ALICE is during injection handshake)
  • if there is no alarms related with LHC exchange project (up to 6 minutes after the Post Mortem procedure started)
  • The status of the Beam Permit. If it is red, then arm the Beam Permit manually, inform Shift Leader and DCS oncall (by email during the night)

The injection permits are rearmed automatically after Post Mortem when:

  • ALICE is SAFE and
  • ALICE did not caused the beam dump and
  • LHC injection handshake is in 'injection' phase (the status is ‘LHC injection ready' or 'LHC injection imminent' after the command 'CONFIRM inject' has already been sent from ALICE)
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