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Reports until 00:42, Saturday 25 February 2017
H1 PSL (PSL)
corey.gray@LIGO.ORG - posted 00:42, Saturday 25 February 2017 - last comment - 09:47, Monday 27 February 2017(34395)
PSL Down!

Just as I submitted the Shift Transition Summary, the PSL Went Down (Flow Sensor #1 for Crystal Chiller; with the cap popping off & water geyser-ing out).

I have put us in the CORRECTIVE MAINTENANCE Observatory Mode State.

I left a voicemail with Jason at 12:38am local time.  This requires a PSL Expert for recovery.  Once we have a PSL Expert available to assist, it should take us ~30-60min to get the PSL back and then another 30-60min to get H1 back to NLN.  

I've also appraised the LLO Operator of our status.  

Comments related to this report
corey.gray@LIGO.ORG - 03:50, Saturday 25 February 2017 (34397)OpsInfo, PSL
Link

Lockloss at 8:38utc.

Got a hold of Jason.  On phone with Jason from 2:35-3:10am to restore the PSL.  Some Notes:

  • He had trouble ssh-ing into the usual opsws1 & 2 computers.  Able to ssh into opsws12 (even though it had an odd message)
  • "Head 1 Flow Error" (again)
  • Topped Off Crystal Chiller with 400mL of water
  • Jason needed to bump up pump diode currents for pump diode boxes (something he planned to do on next maintenance day).
  • Out for CORRECTIVE MAINTENANCE from lockloss to NLN for about 3hrs.
  • New FRS created:  #7499
  • 11:08utc (3:08am)Back to locking
    • One oddity:  Had an HAM6 ISI WD Trip during the DRMI_ASC_OFFLOAD step!
  • ACCEPTED SDF difs for:
    • ISS RefSignal:  was -1.03, now -1.14.
    • CS ECAT PLC2:  H1:IMC-REFL_SERVO_IN1GAIN  was -7, now -8.  Can we ignore this channel?  It's been changing by 1.0 every lock lately.

Back to OBSERVING at 11:44utc (3:44amPST)

david.barker@LIGO.ORG - 11:02, Saturday 25 February 2017 (34402)
Link

opsws1 and opsws2 have been replaced by zotac machines with new names. Best to use opslogin when logging in remotely.

david.barker@LIGO.ORG - 11:07, Saturday 25 February 2017 (34403)
Link

I could not reproduce the problem with opsws12

vernon.sandberg@LIGO.ORG - 08:31, Monday 27 February 2017 (34430)
Link

FRS ticket is: Ticket 7499 - PSL Tripped Due To Head 1 Flow Error

https://services.ligo-la.caltech.edu/FRS/show_bug.cgi?id=7499

 

jason.oberling@LIGO.ORG - 09:47, Monday 27 February 2017 (34432)
Link

This trip appears to have been caused by the flow reading from the Laser Head 3 flow sensor dropping below the trip point and therefore tripping the "Laser Head 1-4 Flow" interlock.  This is in contrast with the previous trips from 2-20-2017, which were caused by the flow reading from the Laser Head 2 flow sensor dropping below the trip point.  The first attachment shows all of the active laser head flow sensors as well as the "Laser Head 1-4 Flow" interlock that caused the trip.  It is obvious that the flow read by the Laser Head 2 flow sensor was the cause of the interlock trip.  The second attachment is a slightly zoomed in view of the Laser Head 3 flow sensor signal and the "Laser Head 1-4 Flow" interlock.

In addition, while restarting the laser I had difficulty injection locking the PSL; it took 3 attempts to injection lock the PSL.  I believe this was due to drop in laser power due to the natural decay of the output power of the pump diodes.  To alleviate this I increased the HPO pump diode currents by 0.5A each.  I had planned to do this during the 2-28-2017 maintenance window, but it was necessary at this time to maintain stability of the injection locking.  In the interest of returning to OBSERVING ASAP, I did not temperature tune the pump diodes; this will be done during the 2-28-2017 maintenance window.

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