daniel.sigg@LIGO.ORG - posted 12:41, Tuesday 15 January 2019 (46425)
Second Loop ISS Parameters Adjusted
In order to minimize the transients when switching the second loop ISS on, the following parameters were changed:
| Parameter | New | Old |
|---|---|---|
| H1:PSL-ISS_SECONDLOOP_PD_CAL_GAIN | 1.0 | 1.2 |
| H1:PSL-ISS_SECONDLOOP_AC_COUPLING_DRIVE_OFFSET | 0.0 | 40.0 |
| H1:PSL-ISS_SECONDLOOP_AC_COUPLING_DRIVE_TRAMP | 0 | 3 |
| H1:PSL-ISS_THIRDLOOP_OUTPUT_OFFSET | 540 | — |
| H1:PSL-ISS_SECONDLOOP_AC_COUPLING_INT_BIAS | 240 | 175 |
| H1:PSL-ISS_SECONDLOOP_AC_COUPLING_OFFSET | –5 | +2 |
Furthermore, the gain of the cts2W section in the H1:PSL-ISS_SECONDLOOP_PD_CAL filter module was changed from 0.00155 to 0.001018. This calibrates the in-loop ISS PD array to the same power as the input to the IMC.
The attached plot shows how how the AOM diffraction power reacts when the second loop ISS is turned on and when the input power is changed from 2W to 30W.
Non-image files attached to this report
