Reports 1-1 of 1 Clear search Modify search
AdV-AEI Squeezer Integration (General)
sorrentino - 19:32 Friday 12 July 2019 (46340) Print this report
Recovery of SQZ after B1 photodiode swap

Opened SQZ fast shutter at 11:49 UTC. Then acted to select B1_PD2 for cc and AA loops:

 

- Acl commands: 

Under SQZ_CC_Ctrl: 'Photodiode:Use B1_PD2_7MHz’

Under SQZ_SDB2: 'AA Phase:Use B1_PD2_7MHz’

 

- Init file of SQZ metatron node:

PD_select = 2

 

- ipython commands to /virgoDev /AEI SQZ/SQZ init.py: 

SQZ_PLL_AA.B1_7MHz_mag.B1_PD1_7MHz_mag=0

SQZ_PLL_AA.B1_7MHz_mag.B1_PD2_7MHz_mag=2

(I did not change the config. file of SQZ_PLL_AA server to avoid reloading the server now; should be done e.g. at next maintenance)

 

Check of cc loop with gain 55, the loops behaves correctly.

 

Scan of cc phase (see attachment) with slow AA servo. Measured squeezing is around 2.7 dB.

 

Manual check of AA servo with dither lines, the loop behaves correctly. Set points of slow AA servo updated on Metatron init file. 

 

Set point of slow cc phase loop updated to 0.1e-3

 

As the SQZ system works correctly with manual commands, I ask the metatron state LN3_SQZ at 14:12 UTC.

 

However the automation does not reach the final state, because the SQZ node keeps waiting for 7 MHz magnitude to reach the threshold (I realized that this threshold is still based on B1_PD1). In agreement with Matteo, to avoid sending the ITF in down for the moment I leave the SQZ metatron node in the state “Injecting squeezing”. 

 

SQZ system is controlled properly.

Images attached to this report
Comments to this report:
vardaro - 16:26 Monday 15 July 2019 (46375) Print this report

When Friday Fiodor tried to inject squeezed light into the ITF with the automation the system fall in stuck. 

The problem was that the SQZ_MAIN node in the State SQZ_INJECTING (index 120), thus the ITF_LOCK node was in stuck in the state ENGAGING_SQZ (index 167).

In the state SQZ_INJECTING, SQZ_MAIN checks if the CC is closed, the AA is closed and the squeezed vacuum states are correctly injected into the ITF:

  • from line 782 to 786 the CC is checked
  • from line 788 to 795 the AA is checked
  • from line 803 to 808 the level of the 7MHz mag is checked (this is a double check on the AA and on the CC)

Friday I forgot to move these controls from B1_PD1 to B1_PD2. The same adjustment must be performed in the state SQZ_INJECTED (ndex = 130)

Here below the list of modified lines:

  • line 782 and 840: from  sqz_b1_pd1_I = ezca.get_channel('SQZ_B1_PD1_7MHz_I_50kHz') -> sqz_b1_pd1_I = ezca.get_channel('SQZ_B1_PD2_7MHz_I_50kHz')
  • line 803 and 862: from  sqz_mag = ezca.get_channel('SDB2_B1_PD1_7MHz_mag_FS_50Hz') ->  sqz_mag = ezca.get_channel('SDB2_B1_PD2_7MHz_mag_FS_50Hz')

I'm preparing an update of the SQZ_MAIN node that performs all the adjustments descirbed int this entry and in the Fiodor's one only by changing the parameter "PD_select" in the SQZ_MAIN.ini file (line 63 section [SHUTTER_OPEN]).  

Search Help
×

Warning

×