[Ushiba, Lucia, Kokeyama, Eleonora]

CONCLUSION:  the four loops to control HARD and SOFT mode for Pitch and Yaw of X ARM are closed using 17Mhz REFL WFS: they seem to work fine.

We followed the same procedure used for pitch loops (#entry 11537)

We measured the following sensing matrix by injecting a line at 0.1 Hz (ampl: 50 count):

Then we inverted it to obtain the ASC input matix:

(Note that, according to our reference system, the HARD mode is excited acting on ETMX and ITMY with the same sign, SOFT with opposite sign. For pitch it is the opposite.)

Then, we closed the loops with simple integrators and verified that they work well.

We estimate that UGF is about 50mHz for SOFT and 20mHz for HARD loop. The measurement was done by measuring the time taken by the loop to recover the aligment when injectig a offset.

We also edited the ASC guardian. Now we can request  "X_ARM_ASC_LOCKED"  where all the four loop are engaged.