Kiwamu, Sheila

• We have 4 asc loops working for DRMI now, which seems to greatly help with the stability by bringing us to a good alingment.
• DRMI was locked on 3F, and is quite stable
• We have been able to lock ALS COMM +DIFF and DRMI on 1F, but not for long.
• All of this was at 10W

DRMI ASC helps stability

We have REFL A 9I going to PRM with a gain of 1e-3 in yaw, 1e-4 in pitch, and AS A 45 Q to the BS with a gain of -5e-5 in pitch and 1e-3 in yaw.   We looked at using REFL 45 I to feedback to the SRM, but the refl B signals have a large offset, and the refl A signals don't seem sensitve to motion of the SRM. We checked the phasing of the rel 45 wfs, (it was already good) and set the dark offsets, but this didn't help.  The four loops that we do have are working well, in the attached screen shot the loops come on at about -30 seconds, and bring us to a good build up.  After this, DRMI is stable and we have none of the mode hopping problems that have been plauging us,and preventing us from locking most of the day today.  Since taking that screen shot I've edited the guardian to bring the ASC on faster, because sometimes we loose the lock due to mode hopping problems before the asc comes on.  The slowest part is the AS WFS centering servo.  These asc loops are all in the gaurdian, as well as offloading, but the user has to decide when they have done their job and manually request offloading for now.

Stable 3F DRMI

After getting the drmi stable, on 1F, we moved it to 3F to confirm that it is stable after the improvements Kiwamu made last night.  That was easy, the gaurdian did it right away without any problems.  It was locked on 3F and left alone for a half hour with no disturbance, from 5:21:25 Sept 10 UTC to 5:51:07.  This is in the middle of almost 2 hours of locked DRMI.
 

DRMI+ALS

After this we attempted to lock DRMI with the arms controlled by ALS.  We had some sucess locking ALS without the ezca servo, (and slow feedback from the end station PDH).  but the slow feedback needs some work (it misalings the arms).  Kiwmau decreased the ALS DIFF gain from 0.8 to 0.5, (already in the gaurdian) which helps prevent saturations, and lets diff lock stably.  We were able to lock both COMM +DIFF+ find the IR resonances, offset the COMM VCO by 500 Hz (which is only 250 Hz in IR) and align PRM and SRM.  We couldn't engage the ASC like this.  We locked DRMI serveral times like this, but it quickly drops because of the mode hopping problem.