Yesteday, after the MC2 model was replaced, recompiled and burt restored to the settings of the preceeding night, we noticed a change of behaviour of the locking loop. It would no more lock easily with the usual settings, and with the higher gain settings it would trigger an oscillation at 21 Hz that we didn;t observe before. Today Matt worked at re-measuring the cross-over frequencies and re-tuning the filters and we'll write an entry about the changes he made and the new suggested operating settings.

In the meanwhile, I'm leaving the IMC locked for the weekend with mild gains, so to increase the chances of a spontaneous re-lock should an un-lock occour:

- common mode board: common gain at -5 db, compensation enabled, boost disabled, fast gain to -2 (as always)

- MC2: MC3_LOCK filters 5 and 8 engaged, gain to -1000; MC2_LOCK filters 2, 3 and 4 engaged, gain 0.03.