J. Kissel
Following LHO:85273, I realize I've lost track of which 6-OSEM top-mass suspensions have had their damping loop gains augmented through commissioning efforts. All of the below suspensions have had their loop control filters updated with a "Level 2.0" design which, during the upgrade from Level 1.0 to Level 2.0, have their EPICs gains reset to -1.0 (and any tuning of gains is built into filter banks). However, because it's far easier to check, revert, and set without knowing details of the frequency dependence of the loop shaping, it is typical to adjust the overall loop gain by increasing or decreasing the EPICs gain in the [M0/R0/M1]_DAMP_[DOF] banks, and then check the impact on ISC loops, including the DARM noise performance and ASC or ISC loop stability.
Here's a list of the current status of all top mass DAMP gains for QUADs, Triples, and Doubles that have a 6-OSEM sensor/actuator array:
{'ETMX M0': [-1.0, -1.0, -1.0, -1.0, -1.0, -0.5], # Aug 2023 commissioning LHO:71927
'ETMX R0': [1.0, 1.0, 1.0, 1.0, 1.0, 1.0], # "Gain" filters have the feedback sign in it, rather than the EPICs gain
'ETMY M0': [-1.0, -1.0, -1.0, -1.0, -1.0, -0.5],
'ETMY R0': [1.0, 1.0, 1.0, 1.0, 1.0, 1.0], # "Gain" filters have the feedback sign in it, rather than the EPICs gain
'ITMX M0': [-1.0, -1.0, -1.0, -1.0, -1.0, -0.5],
'ITMX R0': [1.0, 1.0, 1.0, 1.0, 1.0, 1.0], # "Gain" filters have the feedback sign in it, rather than the EPICs gain
'ITMY M0': [-1.0, -1.0, -1.0, -1.0, -1.0, -0.5],
'ITMY R0': [-10.0, -10.0, -2.0, -0.3, -0.1, -0.1]} # "Gain" filters are OFF, these are taking the place of those filters
{'BS': [-1.0, -1.0, -1.0, -1.0, -3.0, -3.0], # P and Y gains have been this way since 2015 at least
'MC1': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0],
'MC2': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0],
'MC3': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0],
'PRM': [-0.5, -0.5, -0.5, -0.5, -0.5, -0.5], # Aug 2023 commissioning, LHO:72130, LHO:72106
'PR2': [-0.5, -0.5, -0.5, -0.5, -0.5, -0.5], # |
'SR2': [-0.2, -0.2, -0.2, -0.2, -0.2, -0.2], # |
'SRM': [-0.5, -0.5, -0.5, -0.5, -0.5, -0.5], # V
'FC1': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0],
'FC2': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0],
'PR3': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0],
'SR3': [-0.5, -0.5, -0.5, -0.5, -0.5, -0.5], # Aug 2023 commissioning
'TMSX': [-3.0, -1.0, -1.0, -1.0, -3.0, -1.0], # L and P gains have been this way since 2015 at least
'TMSY': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0],
'OMC': [-1.0, -1.0, -1.0, -1.0, -1.0, -1.0]}
Even though the gains seem to be quite scattered and inconsistent at first, most have either been that way through all observing runs to date or were adjusted during a concerted Aug 2023 commissioning effort by Gabriele and Elenna.
