Elenna, Sheila, Louis, TJ, Ryan Short
We have reset the alignment references in full lock, and expect that we should be able to set the guardian to ANALOG_CARM and it should work automatically. Our locks are short, 15-20 minutes.
- Elenna updated ISC_LOCK to lower SRCL gain by factor of 0.6 in carm_5_pm (lowers 3f matrix value)
- Elenna updated PRC1 P and Y gains in ISC_DRMI guardian during DRMI ASC engagement to gains of 10 and 4. This loop has been very slow and I have engaged these gains multiple times by hand, so they should be fine
- Asked TJ to lock XARM and we paused there to check the phasing of REFL_{A,B}RF9. Louis placed an injection at 8.125 Hz into LSC-XARM_EXC with an amplitude of 10 counts. We increased the REFL_A phase by about 20 degrees (to 44.97) & increased the REFL_B to 100.78 (from about 94 deg) (sdf attached). We had plenty of room to adjust the REFL_A phase but ran out of range for REFL_B. We think we could do better if we could introduce some more phase on REFL_B. I didn’t get a chance to get screenshots of the REFL_{A,B} power spectrum with the injection.
- Measured TR_CARM at CARM_5PM, we lost lock a few times in the transition to REFL9 or right after getting to resonance. Changed TR_CARM offset forCARM to REFL from 48 to 52. We have sometimes been manually stepping this to 54 based on looking at the TR_CARM to TR_REFL transfer function.
- We stepped through ANALOG_CARM steps, made two changes:
- Moved the engagement of the common compensation filter until after the gain was increased. This filter has a 4kHz zero and at the time the guardian would have engaged it we had a 3kHz ugf. The guardian steps would later increase the ugf to 10kHz, I’ve moved the filter there in the guardian and followed this procedure by hand.
- Commented out the 23 dB gain increase for the IMC(!).
- Elenna walked alignment while we were locked based on ASC error signals, and set green references, SDF attached.
- Fellows are damping violins.
- Elenna checked POP9 phasing, it looks good, POP 45 needs adjustment (lost lock).
Ryan and I tried running carm to analog, but we think the guardian changes Sheila made hadn't been loaded because the IMC REFL servo gain started ramping up the 24 dB that we earlier determined was unnecessary. Also, then I did load the guardian and there was a code error in carm to analog. I fixed the error and confirmed that the 24 dB gain change was commented out.
We had one lockloss at TR carm for a mystery reason again.
Next lock we ran carm to analog successfully! I then drove an 88 Hz line to check the POP RF45 phasing. I adjusted it about 40 deg, see attached screenshots for measurement and SDF.
I decided to check that the matrix values on the vac 1f signals were appropriately gain and phase matched for MICH/PRCL/SRCL. We had a lockloss while I was setting up the measurement. We've had many locklosses while sitting on resonance like this but nothing looks immediately unstable.
Next lock I just decided to go for it, and I ran the DRMI to POP state line by line. Success! Then, I manualed to DARM OFFSET because I forgot the order, and everything started saturating. Ryan and I realized too late that it is probably some funny business with the darm offset and ASC being in a certain order. Every test mass saturated so my guess is something went wrong with DHARD. I should have just disengaged the DARM offset since it was a slow ring up but I thought of that too late.
