At the beginning of the morning I increased PRCL gain from 11 to 22, since the UGF was low (23 Hz) and very close to unstable. Gain peaking was visible in the PRCL error signal.

In nominal low noise, I did some LSC injections (with the feed-forward paths on):

PRCL noise 1224852731 Oct 29 2018 12:51:53 UTC
           1224853333 Oct 29 2018 13:01:56 UTC
DARM noise 1224853376 Oct 29 2018 13:02:38 UTC
           1224853999 Oct 29 2018 13:13:01 UTC
MICH noise 1224854031 Oct 29 2018 13:13:33 UTC
           1224854630 Oct 29 2018 13:23:32 UTC
SRCL noise 1224854656 Oct 29 2018 13:23:58 UTC
           1224855262 Oct 29 2018 13:34:04 UTC

Then, to investigate the origin of the SRCL modulation, I injected a 20 Hz and a 200 Hz line (simultaneously) in SRCL1

SRCL line 20Hz (ampl 1.0) + 200Hz (ampl 0.3)
Started at 1224856157 Oct 29 2018 13:48:59 UTC
Stopped at 1224865128 Oct 29 2018 16:18:30 UTC

During the period with the two lines on, I injected angular motions at 100 mHz, with amplitudes large enough to be the dominant motion in the ASC input signal time series. Times and amplitudes are below

DHARD_P freq 100mHz ampl 30     1224856631 Oct 29 2018 13:56:53 UTC
                                1224856969 Oct 29 2018 14:02:31 UTC
DHARD_P freq 100mHz ampl 100    1224856989 Oct 29 2018 14:02:51 UTC
                                1224857292 Oct 29 2018 14:07:54 UTC
DHARD_Y freq 100mHz ampl 100    1224857342 Oct 29 2018 14:08:44 UTC
                                1224857642 Oct 29 2018 14:13:44 UTC
CHARD_P freq 100mHz ampl 300    1224857723 Oct 29 2018 14:15:05 UTC
                                1224858097 Oct 29 2018 14:21:19 UTC
CHARD_Y freq 100mHz ampl 300    1224858151 Oct 29 2018 14:22:13 UTC
                                1224858453 Oct 29 2018 14:27:15 UTC
DSOFT_P freq 100mHz ampl 0.003  1224858556 Oct 29 2018 14:28:58 UTC
                                1224858860 Oct 29 2018 14:34:02 UTC
DSOFT_Y freq 100mHz ampl 0.003  1224858915 Oct 29 2018 14:34:57 UTC
                                1224859218 Oct 29 2018 14:40:00 UTC
CSOFT_P freq 100mHz ampl 0.001  1224859297 Oct 29 2018 14:41:19 UTC
                                1224859689 Oct 29 2018 14:47:51 UTC
CSOFT_Y freq 100mHz ampl 0.002  1224859748 Oct 29 2018 14:48:50 UTC
                                1224860275 Oct 29 2018 14:57:37 UTC
MICH_P freq 100mHz ampl 1000    1224860461 Oct 29 2018 15:00:44 UTC
                                1224860804 Oct 29 2018 15:06:26 UTC
MICH_Y freq 100mHz ampl 1000    1224860840 Oct 29 2018 15:07:02 UTC
                                1224861204 Oct 29 2018 15:13:06 UTC
SRC1_P freq 100mHz ampl 0.3     1224861289 Oct 29 2018 15:14:31 UTC
                                1224861674 Oct 29 2018 15:20:56 UTC
SRC1_Y freq 100mHz ampl 0.3     1224861709 Oct 29 2018 15:21:31 UTC
                                1224862086 Oct 29 2018 15:27:48 UTC
PRC1_P freq 100mHz ampl 0.03    1224862191 Oct 29 2018 15:29:33 UTC
                                1224862529 Oct 29 2018 15:35:11 UTC
PRC1_Y freq 100mHz ampl 0.03    1224862564 Oct 29 2018 15:35:46 UTC
                                1224862885 Oct 29 2018 15:41:07 UTC
SRC2_P freq 100mHz ampl 0.01    1224862983 Oct 29 2018 15:42:45 UTC
                                1224863283 Oct 29 2018 15:47:45 UTC
SRC2_Y freq 100mHz ampl 0.01    1224863314 Oct 29 2018 15:48:16 UTC
                                1224863615 Oct 29 2018 15:53:17 UTC
PRC2_P freq 100mHz ampl 10      1224863704 Oct 29 2018 15:54:46 UTC
                                1224864005 Oct 29 2018 15:59:47 UTC
PRC2_Y freq 100mHz ampl 30      1224864063 Oct 29 2018 16:00:45 UTC
                                1224864364 Oct 29 2018 16:05:46 UTC
INP1_P freq 100mHz ampl 100     1224864442 Oct 29 2018 16:07:04 UTC
                                1224864743 Oct 29 2018 16:12:05 UTC
INP1_Y freq 100mHz ampl 300     1224864801 Oct 29 2018 16:13:03 UTC
                                1224865110 Oct 29 2018 16:18:13 UTC

Analysis will follow.