Reports until 14:08, Sunday 24 July 2016
H1 ISC (ISC)
jenne.driggers@LIGO.ORG - posted 14:08, Sunday 24 July 2016 - last comment - 15:41, Sunday 24 July 2016(28603)
Locked at 50W on ETMY

[Jenne, Carl, Terra]

To facilitate the damping of the 18kHz ETMX mode, we are currently locked at 50W using ETMY so that ETMX can be swapped to its low noise driver. SRM dither loop is open.

To do this, it's okay to (once IncreasePower is finished) go to Manual mode and select LowNoise_ESD_ETMY. Last week we lost lock trying to do this because this state also (used to) switch the L2 coil drivers to their low noise state, which we aren't ready for.  So, the noise is acceptable for the lownoise ESDs, but not the low noise L2 drivers.  On the to-do list is to decide where in the sequence to put the L2 switching.

PI and other work is ongoing.

Comments related to this report
peter.fritschel@LIGO.ORG - 15:05, Sunday 24 July 2016 (28605)

For the L2 coil drivers, if I understand correctly you are set up to transition to the lowest noise (and lowest range) state, state 3. As an alternative you might transition to state 1, where the ACQ mode is switched OFF, but the low-pass remains OFF. I believe the low-pass is a 1 Hz pole, 10 Hz zero, so this would afford more range above 10 Hz than state 3, and still puts the L2 noise low enough that it's not a significant limit, at least for our O2 goal. See Chris W's entry 28264.

jenne.driggers@LIGO.ORG - 15:41, Sunday 24 July 2016 (28606)

Ah, yes.  I think you had mentioned this, but I forgot.  I'll give that a try.