[DanielS, Jenne, Craig, Georgia, DanB, Cao]

Earlier today, there were tests with the second loop during IMC-only times going up to high power and back down, and that seemed to be just fine.  So, it's unclear why we're having problems with the same settings but the IFO is on.

Daniel noticed that we seem to be losing the ISS when the second loop tries to reclose after having opened due to a saturation (not so surprising - we know we can't close the ISS second loop at high power).  We're still not sure why we're getting a glitch that is causing a saturation, but for our current lock we've removed the checker that opens the ISS, to see if we can sneak through the power-up. 

----> No good.  We lived through the first glitch, but failed on the second glitch a second or two later.  It looks perhaps like the AC coupling loop is going unstable, although you'd think that we'd see this as a problem during the IMC-only tests.

Daniel "changed some parameters" and thinks that the AC coupling should be more "balanced", so we're trying to power up again.  We're still seeing glitches that the guardian responds to by opening the second loop, but then it seems to be able to reclose more smoothly.  So far it's working, and we got to 20W okay.

----> Going up past 20W didn't work.  Looks like maybe we could try waiting longer after the ISS second loop is turned off before turning it back on, so that the loop has a chance to recover from the transient that happened when the loop opens. 

This lock, we're going to try going all the way to full power, and then engaging the second loop.  Since we've been able to close the second loop several times during power up last lock as guardian noticed saturations and opened the loop, perhaps we can close it for the first time at full power. 

----> We got to 20W again okay, although we see the same spikes up in PRG that we had been seeing at the same time that the ISS was being bad during the last few locks.  Rotation stage doing something funny when it starts or stops moving?  But we're not seeing anything weird in the IMC transmitted power, which I'd expect to see if there was a problem with the rotation stage.  We're going up to max power, but the glitches make DARM drown out the ADS lines, so I turned off the ADS loops during the last part of powerup.  We were able to get to 37W. 

----> Georgia sees strange glitches in IM4 trans and MC2 trans, although it is still not in the power readout on the PSL table. 

----> Craig just plotted the IMC-REFL_SERVO_FASTGAIN, and it's clear that the glitches are happening when the gain is changed to compensate for the higher power.  Craig also points out that if the CARM gain is marginal (too high, or too low), then we'll expect to be more suceptible to these kinds of glitches in the IMC/CARM loops.

----> We were able to close the ISS second loop after we had completed the Maximum_Power state! (I just selected ISS_ON in the IMC guardian after we had arrived at and completed MaxPower in ISC_LOCK.)  Hooray!  As DanB put it "that was surprisingly uneventful". 

----> We are now at Nominal Low Noise (without the squeezer).  Squeezer team has the IFO to inject squeezing, optimize, and do some of the before-Friday measurements.

Separate note on alignment:  The alignment seems to be deteriorating.  It's taking a little longer each lock for DRMI to acquire.  Although, 'longer' has meant 2-4 min, rather than less than 1 min that we've been having all afternoon, so I feel bad complaining too much!