Reports until 17:55, Monday 22 July 2013
H1 ISC
kiwamu.izumi@LIGO.ORG - posted 17:55, Monday 22 July 2013 - last comment - 18:07, Monday 22 July 2013(7164)
BS aligned

[Stefan, Jeff K., Kiwamu]

 We have aligned the BS this afternoon to maximize the amount of H1:ALS-C_TRY_A_DC.

This took some time since there was some confusion in the BS oplev and BS HEPI.

 

Current alignment biases :

H1:SUS-BS_M1_OPTICALIGN_P_OFFSET = -23
H1:SUS-BS_M1_OPTICALIGN_Y_OFFSET = 9
 

Current oplev nominal readout :

H1:SUS-BS_M3_OPLEV_PIT_OUTPUT ~ 5
H1:SUS-BS_M3_OPLEV_YAW_OUTPUT ~ 52
 

After aligning BS, H1:ALS-C_TRY_A_DC_VOLTS went to 0.3 which is higher than the value these days by a factor of 3. Also I see the red transmitted light becoming brighter as I aligned BS. This indicates that we are going back to the previous good alignment.

Before maximizing it we accidentally screwed up the BS alignment. It seems before Thomas centered the BS oplev the BS HEPI tripped for some reason. Therefore unfortunately the oplev centering was done with the wrong alignment. This complicated our alignment. Jeff untripped the BS HEPI with the intentional offsets enabled in V1 and V4 actuators which is the nominal configuration these days. Then we recovered the BS alignment by adjusting the top mass alignment biases. At the beginning we brought BS to roughly a good alignment by looking at the oplev trend and subtracting the offset introduced by the centering business. A fine alignment was done by maximizing H1:ALS-C_TRY_A_DC.

Comments related to this report
jeffrey.kissel@LIGO.ORG - 18:07, Monday 22 July 2013 (7166)
Link 

We were able to get H1:HPI-BS (in BSC2) running on Level 2, by 
- Running "ctrlDown BS"
- Resetting all watchdogs
- Turning on the master switch
- Slowly ramping on the offsets using the master gain (which appears not to be controlled or used by the command scripts)
- Hitting "isolate BS lvl2"

The offsets buried in the V1 and V4 actuator filter banks, which are +2000 and -10000, respectively, were the major source of the H1 SUS BS misalignment.

In case you missed it (like I did), Of the HEPIs involved in HIFO-Y,
H1 HPI ETMY (in BSC6)
H1 HPI BS   (in BSC2)
H1 HPI HAM1
are unlocked and floating, and controllable.
H1 HPI ITMY (in BSC1)
H1 HPI HAM2 
H1 HPI HAM3
are locked.