J. Kissel, with A. Staley (remotely again) After fighting the IMC for quite a bit (see LHO aLOG 16005), Hugo wanted to set up a simple MICH lock in order to test his recent updates to the ISI guardians which allow for switching the ISI BS's stage 2 GS13s from high gain to low gain and back, without breaking the MICH lock (See results in LHO aLOG 16007) but I wanted to put down what needed done before I was able to restore a signal at the AS port, as it was left in an unknown & undocumented state from last night's Koji / Dan commissioning activities. - Request ISC_DRMI guardian to DOWN. It had been left in "LOCK_DRMI_1F," which among other things, was dividing the input power by two three-five seconds after the IMC locked. - Request ISC_DOF guardian to DOWN. This restores all globally controlled suspensions that should be to MANAGED (PRM, PR2, BS, SR2, SRM) - Clear all DRMI WFS offsets from the M1 LOCK P and Y banks of the BS HLTS and HSTSs (which had seemingly random in size and DOF, some rather large, steering the beam who knows where) - Change the ramp time to something large (like 10 [sec]) - Remember the gain value - Set gain to zero - Clear filter history - Restore gain - Request MICH_DARM_LOCKED of the LSC_CONFIGS guardian. - Clear history DC centering on for the IFO WFS - Open ASC overview - Open DC CENTERING (smallish, blue button, in the middle of the screen) - Pull up H1:LSC-ASAIR_A_LF_OUT_256_DQ on a live dataviewer trace, and/or pull up AS port camera (sitemape > CDS > Digital Video Cameras > H1 AS Air > ! Video Control > Launch Fixed Video) - Wait patiently while relevant optics swing into position (may take 15-30 seconds) - Once locked (which happens reliably automatically), you need to tune the BS alignment -- but no more than 0.1 to 0.2 [urad] in either pitch or yaw. Look for 01 modes to disappear, and leave the camera dark, and the AS AIR signal (H1:LSC-ASAIR_A_LF_OUT_256_DQ) to be in the -20 to -15 region. I've left the functional parts of the IFO in this state -- with Simple Michelson locked on a dark fringe.
The large offset in the M1 P,Y LOCK is due to the fact that guardian has not been fully updated since the ASC loops have been modified; the guardian doesn't know to clear the history of these filters which now have an integrator. This has been on our to do list.