I did actuator balancing of IM in ITMX.

First, I change the gain in TM OpLev and rewrite sensing matrix based on results we got last week (klog 17627).
Then, to balance actuator, we got power spectrum of WIT (K1:VIS-ITMX_TM_WIT_{P,Y}_DQ) and calculate how we set the value of gain of IM COILOUTF (K1:VIS-ITMX_IM_COILOUTF_{H1,H2,H3,V1,V3}_OUTPUT).
The frequency of the excitation signals are set to 0.1 Hz, which is below the resonant frequency of the lowest mode of the cryogenic payload.
(We didn't measure V2 because there is no sensor.)
We excited Y (3000 counts), and P (14000 counts) resonant mode and cut excitation signal.
The spectrum we got is Fig1 and 2 (File is in /users/VISsvn/TypeApayload/ITMX/Spectra/20210729).

By this spectrum, we got values of magnitude at peak:
H1 48.4604
H2 47.0958
H3 47.5276
V1 66.5728
V3 68.4035

From this value, we determined the gain like below (Fig 3)
H1 -0.972
H2 1.000
H3 0.991
V1 -1.000
V3  0.972

After the measurement, we reverted the TM TILT OpLev gain and diagonalization matrixto keep the good OpLev value.
Then, I accepted the change of COILOUTF gain.