After scattered telephone game with Hugh, Jeff, and Shiela, I've restored the seismic configration to WINDY by requesting the BRS damping to be disabled manually, setting ISI ETMY's node to BLEND_QUITE_250_SC_BRS, then requesting the global SEI manager to go back to WINDY.

We should consider re-writing / editing the configuration node so that it's fine with BRS damping. From what Hugh says, when the BRS Y damper is on, we, at most, reinject some noise at around the BRS's suspension resonance at ~6-8 mHz. I have a hard time believing this would cause problems in the observational band. 

@DetChar -- this would bne a good day / couple of hours to check the differnec between damping ON vs OFF, since wind has been consistently 20-30 mph for about 10 hours now.

Configuration changes to as described above at 2017-06-16 20:35 UTC.

HMMM, do we turn off BRS when it starts damping?

The Beam Rotation Sensor damping turns on when the velocity of the BEAM hits a threshold; Jim may have this disabled to only damp when we are not in observing.  So the following plots have the BRS velocity, DAMPCTRLMON (~3000=damping on, ~8000=damping off), wind speed, Sensmon range, and (on the second plot) the SENSCOR GAIN (indicates BRS signal going into senscor)

So damping came on this morning ~1100utc.  First plot shows 3 hours around this time when the wind was not quite averaging 20 but occasionally gusting to 30.  The damping came on when the BRS velocity hit 2000  and rapidly brought the velocity down and shut off after less than 20 minutes. On the SENSMON Range graph is also a 500 point average of the range in green and the DAMP signal overlain.  I don't see a definitive impact on the range by having the damping on but maybe one could argue that the wind velocity has chilled some too after the damping came on.  Overlaying the averaged range on the wind does not suggest any strong sense at this steady wind.  The BRS was NOT taken out of Sensor Correction during this damping.  Hmmm

The second case seen on the 2nd plot (6 hours long) is when the wind was apparently strong enough to prevent the BRS from damping down.  This damping started about 1630utc.  It damped for three hours before achieving stop criteria.  After 105 minutes, the operator switched the ISI_CONFIG to WINDY_NOBRSY.  This is seen in the additional channel on the plot.  Right about that time the range started to increase but I thought it sort of looks like the wind was also turning around.  So the wind was running averaged (480sec), then inverted, multiplied by 2.5 and shifted to overlay the Range trace (purple trace).  Pretty much looks like the range is directly correlated to the wind speed.

So, I don't think there is a strong argument to turn off BRS/SC when the BRS Damping comes on based on the range.  Maybe when the wind is so strong that damping is not effective, the result is the same.

There are few points I want to clear up.

1. The damping does NOT get turned off while we are observing, probably a bad idea to leave this off while we are running, as the BRS will ring up on it's own. I just noticed that there was a ~8mhz signal in the arm, and when I checked BRSY, the damping was still off after Jeff's work earlier and the BRS was very rung up. If no one had caught this, the BRS could have gotten into a state where it was unusable for a long time. Unless someone has a compelling reason for us to do otherwise, we should leave the damping on. If any one is ever unsure about what to do, please call me.

2. I haven't seen any evidence yet that BRS damping has broken a lock or had any very adverse affects on the IFO. I have seen the arm length drives affected when the BRS is damping, I have no idea if this causes scattering or something. I would be interested in talking to some Detchar people about how we can find out if it's problem.

3. If the arm drive at 8mhz  is an issue, we can think about modifying the sensor correction filter to more roll off at these frequencies. The simplest would be adding a notch or something to the filter, we could also tweak the damping parameters some.