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Entry  Tue Jun 25 00:28:52 2013, rana, manasa, Update, LSC, Arm Cavity scan with X-ALS after ALS servo upgrade 6x
    Reply  Tue Jun 25 10:18:34 2013, Mystery Man, Update, LSC, Arm Cavity scan with X-ALS after ALS servo upgrade 
       Reply  Tue Jun 25 11:39:13 2013, Koji, Update, LSC, Arm Cavity scan with X-ALS after ALS servo upgrade 
    Reply  Thu Jun 27 19:17:03 2013, manasa, Update, LSC, Xarm ALS out-of-loop noise ALS_OoL.pdfALS_OoL1.pdf
Message ID: 8741     Entry time: Tue Jun 25 00:28:52 2013     Reply to this: 8742   8772
Author: rana, manasa 
Type: Update 
Category: LSC 
Subject: Arm Cavity scan with X-ALS after ALS servo upgrade 

[Rana, Manasa]

ALS noise suppressed to 1KHz/rtHz. 1kHz RMS.

Plot 1: Scan of X arm by changing offset into Phase Tracker -> Xarm loop. Filter bank ramp time set to 120 s + using a 30 mHz low pass filter. IR beam is aligned to x arm, but not well.

Plot 2: ALS error signal with loop open (BLUE), closed with old filters (PURPLE), and with new, better boost (RED).

Plot 3: Bode plot of new boost (FM10), v. old, sad boost (1:50 pole:zero). RMS is now less than 1 kHz or ~50 pm. (in your face, Kiwamu!)

Changes made to the ALS servo:

1. C1ALS-TRX 

ALS-TRX has been calibrated to read from 0-1 instead of counts in 1000 s. Calibration factor = 1/4500 = 0.00022

2. C1ALS_BEATX_FINE

Old antiwhitening filter has been removed. Added LPF at 1000Hz to remove glitches at high frequencies.

3. C1ALS-BEATX_FINE_PHASE

No changes made.

4. C1ALS-XARM

FIlter FM5 modified. 1000:1 changed to 3000:1

5. Offset for ALS scan were given through C1ALS_OFFSETTER1 with LPF50m enabled.

 

The filter modules of the servo were:

 ALS1.png

ALS2.png

ALS3.png

 

 Next:

Check PZT out range for ALS. Figure out what the deal is with ALS SLOW servos.

Add DQ channels for ALS.

Automatic ALS up script (enable and disable phase tracker included).

 

 

Attachment 1: scan.png  166 kB  | Hide | Hide all
scan.png
Attachment 2: als-x-err.pdf  48 kB  | Hide | Hide all
als-x-err.pdf
Attachment 3: FM10.pdf  20 kB  | Hide | Hide all
FM10.pdf
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