kiwamu.izumi@LIGO.ORG - posted 11:12, Thursday 29 January 2015 - last comment - 11:26, Thursday 29 January 2015(16340)
some maintenance in initial alignment
Ed and Kiwamu,
In the morning of today and yesterday, we went through all the initial aligment steps. In the course of the process, we found that there were a few settings that were hidden and not set correctly. So we made a couplle of modifications on the guardians and filter in order to automate them:
- edited LSC_CONFIGS such that it takes out the 160 dB attenuators (alog 16315) out of ASAIR_RF45 in the LOCKING_X(Y)ARM_IR states.
- edited LSC_CONFIGS such that it sets the whitening gain of REFL_A_RF9 back to 0 dB.
- added a new filter in LSC-ASAIR_A_RF45 in order to compensate the 20 dB attenuation (alog 16334).
- also, added another new filter in LSC-ASAIR_A_RF45 which gives another 20 dB. This got rid of the gain factor of 10.
The attached screenshot shows the current good settings in order to go through the alignment sequence. This configuration should be automatically achieved by the guardians.
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Some additional notes:
We found two failure modes which we did not get a chance to fix the guardians. I will have a close look at them tomorrow morning or next week.
- ISC_DRMI for some reason did not set the PSL power back to the nominal of 10 W even though we requested the DOWN state.
- When locking PRX, LSC_CONFIGS got stuck in LOCKING_PRX even though ASAIR_A_LF exceeded the threshould value.