Den, Evan, Sheila, Hang
We've spent some time on ASC today. First of all we added yesterday's changes to the DRMI ASC (25630) to the guardian, but used the new AS36 A phasing from early this morning. This seems to work fine.
We also measured the sensing matrix for the INP1, PR3, and CHARD in the refl WFS. For pitch, in counts/counts
| CHARD | IM4 | PR3 | |
| 9A | 1.9 | -5.9 | 1 |
| 9B | 2.3 | 4.3 | 4.7 |
| 45A | 2 | -4.9 | -2 |
| 45B | 2.4 | 4.0 | -2.3 |
| excitation amp | 3e3 | 100 | 200 |
| demod phase | 0 | 90 | 0 |
Den set this up using the locking oscillator, the excitation amplitude and demod phases used are for future reference. For yaw:
| CHARD | IM4 | PR3 | |
| 9A | -2.1 | 7.8 | -3.4 |
| 9B | -3.3 | -5.1 | -7.8 |
| 45A | -2.1 | 8.3 | -0.4 |
| 45B | -2 | -4.6 | 4.06 |
| excitation amp | 3e3 | 100 | 200 |
| demod phase | 0 | 90 | 0 |
Since Den noticed that the values of the sensing matrix we got for REFL45A were fluctuating (and small compared to the others), we did not use it.
The POP offsets have changed, and right now we are using small offsets in the soft loop error points.
To summarize the last few days, we had some kind of alignment problem perhaps because of a temperature swing in the lvea on tuesday. We have fixed a few things that have been longstanding oddities in our ASC system:
- We now have phases for AS36 and REFL 45 that seem sensible (they mostly within a few degrees for all the quadrants on one head, except for SA36B with has a 20 degree spread.)
- We are now using normal matrices for all the WFS, no more random zeroed quadrants.
- We are no longer switching our AS36 input matrix around as we power up.
This seems like great progress, although we clearly have more work to do increasing gains, and getting rid of some cross couplings between loops. Most of the new settings have been accepted into SDF, and we think all of them are in guardian, which we are about to test.
