Acquire LOCK, get to NOMINAL_LOW_NOISE

Let IFO thermalize for ~2 hour (you can take IFO to observe during this time)

MEASURE THE CALIBRATION:

Go to NLN_CAL_MEAS guardian state in ISC_LOCK guardian
(this will remove you from of observation intent, this is ok, this is what we want)
Set the observatory mode to "Calibration"

INSTRUCTIONS SPECIFIC FOR 2020-01-20:
You're measuring one thing: the IFO ("sensing function") but in two configuration (the templates are ready for both configuration)

However, this one thing requires two measurements: a pcal to something, then "the thing your measuring" to something.
It's imperative that you get each pair of "PCAL" and "thing your measuring" measurements close in time, in the same, thermalized lock stretch.

We usually make routine sensing function measurement in one configuration only but today we are doing it in two configuration
You can use two different lock stretches between two configurations if needed (just in case the lock breaks) but follow instruction above for each pair of measurement within a single configuration. 


FIRST CONFIGURATION (NORMAL)
Sensor Measurements to run:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Measurements/FullIFOSensingTFs/
    2020-01-20_H1_DARM_OLGTF_LF_SS_5to500Hz_15min.xml
    2020-01-20_H1_PCAL2DARMTF_LF_SS_5to500Hz_10min.xml

Gotcha for DARM OLGTF measurement -- watch out for "DTT Disease." Some times, even though the measurement template runs, 
and drive is going in to the interferometer, the reported results will
   - not show up in the loglog magnitude plot (because they're zero) (upper left plot)
   - the phase will be identically zero (lower left plot)
   - and coherence will be zero (upper right plot)
This will be obvious after the first ~5 data points. If this happens, just abort the measurement, and restart.
(There are 40 data points total).

Save these files once the measurement is complete.

SECOND CONFIGURATION (A2L GAIN Off):
Open A2L screen from LSC >> LOCKING >> A2L (right top  in the screen)

Run the following python script to turn the ETMX A2L Gain to zero and confirm that the ETMX A2L gain is zero on the screen.
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Scripts/FullIFOSensingTFs/
    switchA2LGainoff_for_20200120_sensingmeas.py

Sensor Measurements to run:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Measurements/FullIFOSensingTFs/
    2020-01-20_H1_DARM_OLGTF_LF_SS_5to500Hz_15min_A2LGainOff.xml
    2020-01-20_H1_PCAL2DARMTF_LF_SS_5to500Hz_10min_A2LGainOff.xml

Watch for all the gotchas mentioned in first set of measurement

Save these files once the measurement is complete.

NOW BACK TO GENERIC INSTRUCTIONS

You're done!

Take ISC_LOCK guardian back to NOMINAL_LOW_NOISE.
     
Assuming this all works, you should be able to go back in to nominal low noise, 
there should be no SDF diffs, and you can go back to observation intent = YES.

IF there is SDF Diffs on ETMX A2L gain then run the following script to revert the A2L Gain.
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O3/H1/Scripts/FullIFOSensingTFs/
    switchA2LGainrevert_after_20200120_sensingmeas.py

You should now be ready to go back to Observation Intent!!