thomas.shaffer@LIGO.ORG - posted 03:15, Monday 30 November 2015 - last comment - 04:09, Monday 30 November 2015(23821)
Lockloss at DC_READOUT, possibly from OMC
At ENGAGE_ASC_PART3, I noticed that the OMC_LOCK was not in READY_FOR_HANDOFF. Re-requesting it did not seem to help. There was a notification that it could not find the 45MHz sideband. I went through the code and saw that adjusting the OMC-PZT2_OFFSET slider while watching H1:OMC-PZT2_MON_DC_OUT and H1:OMC-DCPD_SUM_OUT could work. I thought I got it to where it needs to be, I manually moved past the FIND_CARRIER step and all seemed well until DC_READOUT.
The initial voltage scan for the PZT was changed from -30 to -24 on Nov 18, I found the sidebands to be at an offset voltage of 25.25V. Not sure if I even really got it, but perhaps this initial value needs to be changed slightly?
The same issue happened the second time around. This time I changed the start scan voltage back to the original -30V in the guardian. Worked first try. This change has been saved and committed.