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The purpose of this document is to expose the plan to commission the piezo drivers installed at the European XFEL. 
The 16 channel piezo drivers (PZ16M) are installed at A1, and A[2-25]M&S LLRF systems.
It makes sense to commission master and slave of one station together, but all PZ16M are independent and can be commissioned in any desired order.

Technical commissioning

Cable checks 

  • verify if one can drive both piezos for each cavity
  • check for any possible cable swaps (i.e. cavity 1 ↔ cavity 5)
  • check for any abnormal cable impedance (i.e. maximum piezo stroke only induces small detuning)
  • all results should be compiled into one unique summary document.
  • tunnel investigations (during maintenance) and possible cable fixes
  • software configuration if needed to identify which piezo can be used (until all problems are fixed) 
  • expected time: 1 hour per station in the BKR, 1 hour per cable investigation in the tunnel 

Alarm checks

  • verify the piezo energy monitoring (PEM) over energy functionality (i.e. 3 sine excitation triggers the PEM)
  • check details of the alarm (channel triggered, delay and reset)
  • all results should be compiled into one unique summary document.
  • follow up on outcome (software configuration if some alarms are not detected, or are too sensitive)
  • expected time: 1/2 hour per station in the BKR

Operation commissioning

Cavity tuning procedure

  • define, test and refine exact tuning procedure (2 hours in BKR, several iterations)
  • define and implement flags to enable, disable automation (via the FSM ?) (2 hours in BKR, several iterations)
    • whenever gradient is changed
    • whenever cavities are retuned

Piezo tuning automation

  • identify frequency and delay for all cavities
  • deploy and configure piezo automation server
  • use test station to validate functionality
  • close monitoring for first week of operation

Exception handling for piezo automation

  • Test the robustness of the piezo automation, in particular in the following conditions
    • absence of gradient (RF trip)
    • wrong detuning computed by diagnostics server (due to pulse cut for example)
    • incorrect information from timing server (misconfigured or absence of trigger)
    • crate reboot
    • optical link communication error
    • cryo not OK
    • cavity detuning is larger than piezo tuning range
    • server communication error (with FSM, with detuning server, with piezo controller server, with llrf ctrl server)

Handover

  • design piezo operation overview panel (for entire XFEL)
  • bring up piezo operation / errors to main operator panels (agree with RC, where / how)
  • define commissioning schedule with RC
  • define handover procedure with RC




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