Engaged DOF1P, DOF1Y and DOF2Y, dithered ITM and ETM, and measured the sensing matrix based on OL (assuming that OL calibration is now correct).
| WFSA | WFSB | |
| ITMP | 82.8 cts/urad | 901.8 |
| ETMP | -430.8 | -1247.8 |
| ITMY | -587 | 671 |
| ETMY | -504 | 292 |
The sign follows the SUS convention that positive PIT = mirror points down, positive YAW = counter clockwise viewed from the top.
As was observed before, WFSA is a good YAW hard mode sensor, WFSB is a good PIT hard mode sensor.
Since neither of the WFSs is good soft mode sensor, I made these:
DOF2P = -4.19 WFSAP + WFSBP
DOF2Y = WFSAY + 1.1 WFSBY
After making these, all four DOF loops were closed and it worked, with one caveat: It seems like DOF2P wants a large offset in order for the green transmission to be maximized. I tried +2500 cts offset and it was good (transmission touches 850 cts). Without this, the transmission stays between 650 and 750.
Unfortunately I cannot give DOF2P an offset before the master switch, and I put this offset in the feedback filter itself. When IFO unlocks the integrator will keep integrating, destroying the IFO alignment.
So I disabled DOF2P input AND offset, and left other three DOFs, for tonight.
It's still slow.