Elenna, Gabriele
We noticed coherence between DARM and INP1_P and INP1_Y. So we redesigned the loops to have a much larger roll-off at 10 Hz and above, for both P and Y
Elenna, Gabriele
Same treatment for PRC2 PIT adn PRC2 YAW, sicne those showed coherence too. Attached plots compare the old and new controllers.
We have adjusted the new filters for PRC2 and INP1 to be used by the guardian from Engage ASC for Full IFO onward. We are using probably a factor 10 less gain for INP1 P now than normal for powering up. This may be a problem, so please keep an eye on ASC stability during power up. Normally we would have the factor 10 gain for INP1 all the way through Max Power, and then the gain would be lowered in Lownoise ASC.
I have accepted these new filters in the observe SDF.
Looks like some low frequency improvement from this change!
Comparison of ASC control signals with the old (RED) and new (BLUE) controllers. CHARD controllers are the same, but the noise improved probably due to the reduction in the other loops' noise
I think we don't see an improvement in INP1_P because we are hitting the numerical limit of the PSD computation
We have successfully powered up with these new loops.