(Alexa, Daniel, Sheila)
We measured the WFS sensing matrix for both PIT and YAW. The matrices were computed by exciting ITMX/ETMX PIT/YAW at 1.5Hz with 0.3 amplitude, and looking at the WFS transfer function. The results can be found in the following DTTs saved in /ligo/home/sheila.dwyer/ALS/HIFOX/WFS/:
- WFS_sensing_matrix_ETMX_PIT_march28_2.xml
- WFS_sensing_matrix_ETMX_YAW_March28.xml
- WFS_sensing_matrix_ITMX_PIT_March28_2.xml
- WFS_sensing_matrix_ITMX_YAW_March282014.xml
Inverting the results gives...
YAW input sensing matrix:
-2.294 -3.155
0.529 -2.604
PIT input sensing matrix:
-0.494 -0.239
0.302 -0.489
These values are in microradians; however the factor of 1e-3 is taken care of in the gain of the filter module. We also adjusted the signs as follows:
- H1:ALS_X_WFS_DOF1_Y_GAIN = -0.001
- H1:ALS_X_WFS_DOF2_Y_GAIN = -0.001
- H1:ALS_X_WFS_DOF1_P_GAIN = -0.001
- H1:ALS_X_WFS_DOF2_P_GAIN = 0.001
Under this configuration, with all four DOFs engaged (DOF 1,2 P,Y) the WFS_A/B_I_YAW/PIT_OUTMON all converge to zero. The lock appears to be stable with a transmission betweeen 950 to 1050 counts. Futher investigation needs to be done...