Attached is a comparison between the measured and modeled open loop of the control applied to the top mass of ETMY in long. The configuration during the measurement was similar as the one took previously (cf aLog 6969), with the damping/filter gain set to 3 instead of 1 for L (config used for running the interferometer). Once again the measurement matches the model, and surprisingly, even with a phase margin of 13º, the system stayed stable for days.

Now that we trust our model, the 2.1 filters will be installed today on ETMY.