Sheila, Hugh (remotely), Niko, Georgia
After an epic battle to reacquire lock (see Niko, Sheila, and Jenne's posts about alignment references and DC centering loop notches), we found a couple of strange SDF differences.
HAM3 and HAM4 GS13's
The GS13's for HAM3 and HAM4 were in a non nominal state, with filter differences for H1:ISI-HAM[3,4]_GS13INF_[dof] for each degree of freedom (H1 H2 H3 V1 V2 V3). The Gain and DWH (de-whitening) filters were on when we reached nln, where nominally they are off. Hugh told us how to fix the problem (sitemap -> ISI -> HAM3 -> Commands -> GS13 !HI). Doing this did not break the lock.
We're not sure how we ended up in this state, maybe after the large earthquake today things were not quite returned to normal?
PRM M3 output filter "differences"
The SDF reported differences with PRM M3 (see attachment), but we found the filters were correct given the state of the coil drivers. Time machining to the last lock, we don't think there was really a difference.
Pretty sure I am to blame for HAM3 & HAM4 SEIs. :-/
Here's what I recall for SEI Land:
- Maintenance was preceded by a big earthquake so the ISI_CONFIG was taken to LARGE EARTHQUAKE via the "big red button" before Maintenance started.
- During Maintenance, Pep was performing some bounce/roll measurements and requested HAM3 & HAM4 SEIs be taken to a nominal state (earthquake seismic effects were at a lower state).
- Since Rahul was performing charge measurements, did not want to touch the end stations.
- Individually took HAM3 & 4 HEPI & ISI guardian nodes to their nominal states.
- After charge measurements, wanted to return ALL SEIs to their nominal state, so:
- Hit Recover EQ button via "green button"
- Then selected WINDY state
After seeing Georgia's alog about HAM3/4, immediately figured this probably due to me. Talked with TJ since he was in the area, and he (& also) Hugh mentioned this is probably due to my not hitting the Recover EQ button (which addresses GS13s). TJ said I could have perhaps taken HAM3/4 to a correct state "by hand", but I did not know how to do it.
Anyway, it's another learning experience.
The recovery script includes a step to put all of the GS13s in low gain which is unnecessary. This means that because HAM3&4 were already isolated when Corey pushed the recovery button, the other chamber guardians handled the sensor gains properly, but HAM3&4 were switched to low gain, and never set correctly by the guardians. I've taken those lines out of the script so this shouldn't happen again.