daniel.sigg@LIGO.ORG - posted 14:53, Tuesday 15 March 2022 - last comment - 13:38, Wednesday 16 March 2022(62235)
OMC DCPD test inputs
The internal DAC cable of the OMC DCPD whiteing chassis, S2101608, was changed to the new one that corrects the polarity.
We hooked up the test inputs for the OMC DCPDs. The excitation channel is called H1:OMC-TEST_DCPD_EXC.
Looking at the compensated transfer functions of both DCPD_A and DCPD_B, the filters are lacking.
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As part of this change we swapped the last 2 DB9 cables at the LSC DAC AI board. This physically swapped the DB9_3 and DB9_4 signals, but this was compensated for in the lsc and omc models. In detail:
| Channel | Old DAC # | New DAC # |
|---|---|---|
| OMC PZT1 Dither (LV) | 12 | 8 |
| OMC PZT2 Drive (HV, servo) | 13 | 9 |
| OMC PZT1 Drive (HV, bias only, PZT3) | 14 | 10 |
| OMC_TEST_DCPD | N/A | 11 |
| ALS-C_REFL_DC_BIAS | 8 | 12 |
| LSC EXTRA_AO_2 | 9 | 13 |
| LSC-EXTRA_AO_3 | 10 | 14 |
| LSC-EXTRA_AO_4 | 11 | unavailabe |
| DuoTone | 15 | 15 |
Adding new filter coefficients from the actual measurements and Dripta's fits in alogs 61823 and 62187. The results look much better.
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