Jennie W, Sheila, Elenna, Georgia, Ryan S.

Even though Georgia and Trever successfully had the OMC ASC working yesterday before they took OMC scans we have again had problems with the ASC today. We don't fully understand why this is as we had tweaked the alignment on Friday in order to ensure the OMC ASC converged without saturating any suspensions.

We turned on the OMC guardian and it complained about no light on the OMC DCPDs.

We turned on DC centering and SR2 loop and then tried to turn on OMC ASC but it saturated the OMC suspension - this may have been because OMC QPD A was completely off the PD. After we turned off the ASC the beamns were centred again on QPD A and B for the OMC but turning on the ASC still staurates OMC suspension.

Tried turning this on again with SR2 loop off and this still happens.

Same with DC centering loops off.

See first attached image of the ASC loops running away.

In the commissioning meeting it was pointed out that the GRD OMC node might have flipped the POS X and ANG Y gains back to the nominal sign which we had changed last week to make the ASC converge.

Elenna and Matt trended the gains and found that this does indeed happen and flipped them back. After discussions with Ryan we note these gains are hard coded into the guardian so we may need to change this is in the code before the run starts but for OMC scans we will just set these manually and also not accept them in SDF yet.

Sheila accepted the change to the QPD pitch and yaw offsets we made last week. That is we switched them off. See second image.