J. Kissel [remotely]

Continuing health checks of the SUS after the Boise EQ (started in, e.g. LHO aLOG 55848 and LHO aLOG 55857), I took top-to-top transfer functions on the main chain (M0) of ETMX. 

This metric reports the suspension remains free of rubbing and functionally normally.

Full data set has been saved to 
    /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGM0/Data/
        2020-04-03_1939_H1SUSETMX_M0_Mono_WhiteNoise_L_0p01to50Hz.xml
        2020-04-03_1939_H1SUSETMX_M0_Mono_WhiteNoise_T_0p01to50Hz.xml
        2020-04-03_1939_H1SUSETMX_M0_Mono_WhiteNoise_V_0p01to50Hz.xml
        2020-04-03_1939_H1SUSETMX_M0_Mono_WhiteNoise_R_0p01to50Hz.xml
        2020-04-03_1939_H1SUSETMX_M0_Mono_WhiteNoise_P_0p01to50Hz.xml
        2020-04-03_1939_H1SUSETMX_M0_Mono_WhiteNoise_Y_0p01to50Hz.xml

Just because it's a pain to gather screenshots, I only post three exemplary DOFs, but every other DOF equally matches the Jun 2018 reference data.

[EDIT] 
Note, while we were measuring ITMX, we ran into trouble with the IOP watchdog. This was a result of the configurations of the SEI systems at the time: 
    - Having HPI OFFLINE, ISI DAMPED is not a typical configuration of SEI system during top-to-top transfer functions, thus
    - The RMS of the raw OSEM signals -- during normal TF excitation -- exceeded the IOP watchdog threshold, triggering the start of the 5 minute countdown.
    - For some reason,  (again atypical) the residual motion after the measurement -- even with SUS damping loops turned back on -- remained large enough to *keep* the 5 minute timer counting
    - Eventually, after 5 minutes, the SEI system was forced to shutdown, tripping its watchdog.

In order to avoid this unnecessary confusion, for this measurement and all subsequent measurements, we've decided to being the SEI managers to ISOLATED_DAMPED, with HPI on an running as normal, and ST1 isolation loops running (sensor correction remains OFF though). With that configuration, and turning the SUS damping loops in between measurements, I was able to successfully complete the above suite without interference from the IOP watchdog.

Also -- as Cheryl correctly remembers, we must turn the Top Mass coil driver state from 2.0 to 1.0 during these measurements to allow for maximum DAC range.
The SUS guardian is in the "FULLY_ENABLED" state, such that M0_TEST outputs can go out, but the OPTICALIGN offsets are NOT engaged (again, to claw back DAC range).
[/EDIT]