J. Kissel, S. Dwyer

As opposed to the ''glitch'' I reported this morning (LHO:84622) which was while the IFO was configured in PRX and ISC loops created a large pitch excursion with M1 drive of the H1SUSBS. We're now seeing stuff that is much more "classic optical lever glitching" with the IFO configured in PRMI, with MICH ASC engaged. See attached. This is after Sheila/Camilla increased the current in the BS oplev laser this morning (LHO:84616)

As a reminder, Beam Splitter optical lever loops are only used in PRMI / DRMI until MICH ASC is turned on. The transition happens in the ISC_DRMI guardian, in the "ENGAGE_DRMI_ASC" (index 80) state; the gain in the ASC-MICH banks are ramped ON in 2 seconds, and the gain in SUS-BS_M2_OLDAMP banks are ramped off with a 20 sec ramp (i.e. it's not that the inputs or outputs are switched on or off).

So, beam splitter optical lever glitching had been particularly painful in the past few days when working in PRMI and/or DRMI without the corner ASC loops on. But, now that we've found a good alignment, and fixed the REFLAIR phase (LHO:84630) we're able to quickly transition to using DRMI ASC, and become insensitive to the optical lever performance -- which continues to glitch.