[Sheila, Jenne, Betsy, TJ]

Today we had a saga of trying to move even closer to center on PR2, however we were struggling to lock DRMI when relocking, so we've reverted to the alignment situation we were in for our long lock last night.  Since that work took longer than anticipated, we still have not yet remeasured our position on PR2 and PRM, so we plan to do that next time we're commissioning.

• We extrapolated from alog 77870 that we needed to move the PR3 yaw slider to a value of -234 urad, which is a further 159 urad more than we had moved so far.  This comes from our measurement noted in that alog that having moved the PR3 slider by 64 urad moved the spot on PR2 by 2.5 mm, and we wanted to move a total of 15mm from our original position. 
• Since we were unlocked anyway from maintenance day, we got the green arms locked (so that we could see the ALS COMM and DIFF beatnotes), and then manual-ed ISC_LOCK to PR2_spot_move.  
  • Aside: later in the day it was noticed by some GDS folks that using this state with index 900 (which is greater than 409) meant that the range was being calculated, but was returning a nonsensical value, because the IFO wasn't actually locked.  TJ changed the index of this state to be -11 so that the range won't be calculated when we're in that state.
• When almost all the way on the PR3 slider to our goal position, verbal alarms warned us that we were saturating IM4.  This is because the PR2_spot_move state watches how much you move the PR3 slider, and applies a scaled change to PR2, PRM, and IM4 sliders. 
  • My plan for mitigating this was to move IM3 to relieve IM4, but since we had fallen off of ASC_POP_A basically as soon as we started moving PR3, we had to walk all the way back in PR3 slider to where we started, in order to see beam on ASC_POP_A.  However, moving just IM3 gives a pretty significant angle change, so in the end I moved a combination of IMs 1-3 to keep in roughly the same place on IM4_trans and POP_A, while relieving the IM4 yaw slider. 
• Went back to moving PR3
• I think around here is when I realized that we had no light on the AS_AIR camera, and also that we had again fallen off of POP_A. 
• Re-reverted about halfway to last nights alignment situation, to get onto POP_A.
• Went 'forward' with PR3 a little bit, moving IMs 1-3 to keep on POP_A and IM4_trans.  Didn't go very far though, since it was getting late in the day.
• When trying to relock, saw that the ALS COMM beatnote was too low, and could not be improved by either moving PR3 or by pico-ing.
  • Went to ISCT1 and touched up the COMM beatnote alignment, and brought it up from -20dBm to about 0dBm.
• We went through an initial alignment and were trying to relock, but it was very nearly impossible to get DRMI to catch lock.  I could get it to catch and hold for 1-2 seconds or so, but only a very few times. 
• In the end, we went back to green arms locked, and I manual-ed again to the PR2_spot_move state, and I moved the PR3 yaw slider back to about where it had been last night.
  • Re-did the IR parts of initial alignment, and saw that the comm beatnote was still good, so no need to go back to ISCT1. 
  • This time we were able to get locked on basically the first attempt.
• I'm not so sure that the attached screenshot is very helpful, but at least it gives a timescale so we can go back and look at some things in more detail later if need be. Also, the y-cursors, if set, are at the value at the end of the long lock that ended just before maintenance today, so you can see that alignment-wise we're pretty similar to where we were last night.