Alexa, Sheila, Stefan We made a little bit of progress in DRMI alignment today. - First we ran the SRY cavity, and commissioned a pointing loop from the ASC_AS_C quad to SRM and SR2. - We used M1 (top mass) actuation because we needed the range, so we switched both SRM and SR2 to MO angular actuation. - We then carefully tuned the output matrix such that we don't rely on the WFS to keep SR2 and SRM aligned relative to each other. - The output matrix is: SRM SR2 PIT -7.08 1.00 YAW 7.12 1.00 Note that this matrix will likely change if we switch M2 actuation. - Then we successfully used this pointing loop in DRMI, even without any SRC WFS running. - The gains were H1:ASC-SRC2_Y_GAIN = 1, H1:ASC-SRC2_P_GAIN = 1, and the input matrix is also 1 (H1:ASC-INMATRIX_P_7_27 and H1:ASC-INMATRIX_Y_7_27). - Next we re-phased the AS 36 and AS45 diodes using a freely swinging Michelson. A snapshot of all four diodes is attached. - Then we started looking into the SRC WFS again: - After many failed trials, we noted that one of the biggest signals for the SRM is AS_A_RF36_Q. But we already used this for the BS. - However when driving the BS we found that it has a different demod phase: The BS signal is maximized for the mix 0.89*I + 0.45*Q (all of AS_A_RF36). The same mix was measured for both PIT and YAW. Thus we switched the BS to this mix. - Finally, for controlling the SRM, we found two signals: AS_A_RF36_Q from before, and AS_B_RF36_I. - Because AS_B_RF36_I is more what I expected, I left the SRM on that one. Not done yet: Adding all this to the Guardian.
I added the SRC2 feedback to SRM, SR2 to the "SRM ALIGN" part of the ISC_DOF guardian. These are also in the DRMI guardian now. The SRC1 feedback to SRM is also in the guardian but for now I have left the gain to 0; the old gains are commented out. In the DRMI guardian, "OFFLOAD_DRMI_ASC" now only offloads the PRC, and MICH wfs since its only works for feedback to M2. I have added an "OFFLOAD_SR2_ALIGNMENT" and "OFFLOAD_SRM_ALIGNMENT" which should offload the M1 stages; this was copied over from ISC_DOF guardian and I have not tested it in this configuration.