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Entry  Mon Sep 20 12:20:31 2021, Paco, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements PRM_PIT_ACT_TF.pdfPRM_YAW_ACT_TF.pdfBS_PIT_ACT_TF.pdfBS_YAW_ACT_TF.pdf
    Reply  Mon Sep 20 14:22:00 2021, rana, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements 
       Reply  Thu Sep 23 15:29:11 2021, Paco, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements BS_PRM_ANG_ACT_TF.pdf
          Reply  Fri Oct 1 14:25:27 2021, yehonathan, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements MICH_PRM_-0.34.pngMICH_PRM_-0.1.png
          Reply  Mon Oct 4 16:00:57 2021, Yehonathan, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements BS_PRM_ANG_ACT_TF_20211004.pdfBS_out_mat_20211004.txtPRM_out_mat_20211004.txt
             Reply  Mon Oct 4 16:10:09 2021, rana, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements 
             Reply  Tue Oct 5 20:04:22 2021, Paco, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements 
                Reply  Wed Oct 6 15:39:29 2021, Anchal, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements 
             Reply  Tue Oct 12 11:32:54 2021, Yehonathan, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements modified_output_matrices_radar_plots.pngnormal_output_matrices_radar_plots.png
                Reply  Tue Oct 12 16:39:52 2021, rana, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements 
                   Reply  Thu Oct 14 13:40:49 2021, Yehonathan, Summary, SUS, PRM and BS Angular Actuation transfer function magnitude measurements BSPRM_Actuation_Radar_plots.pngITM_Actuation_Radar_plots.png
Message ID: 16343     Entry time: Mon Sep 20 12:20:31 2021     Reply to this: 16345
Author: Paco 
Type: Summary 
Category: SUS 
Subject: PRM and BS Angular Actuation transfer function magnitude measurements 

[yehonathan, paco, anchal]

We attempted to find any symptoms for actuation problems in the PRMI configuration when actuated through BS and PRM.

Our logic was to check angular (PIT and YAW) actuation transfer function in the 30 to 200 Hz range by injecting appropriately (f^2) enveloped excitations in the SUS-ASC EXC points and reading back using the SUS_OL (oplev) channels.

From the controls, we first restored the PRMI Carrier to bring the PRM and BS to their nominal alignment, then disabled the LSC output (we don't need PRMI to be locked), and then turned off the damping from the oplev control loops to avoid supressing the excitations.

We used diaggui to measure the 4 transfer functions magnitudes PRM_PIT, PRM_YAW, BS_PIT, BS_YAW, as shown below in Attachments #1 through #4. We used the Oplev calibrations to plot the magnitude of the TFs in units of urad / counts, and verified the nominal 1/f^2 scaling for all of them. The coherence was made as close to 1 as possible by adjusting the amplitude to 1000 counts, and is also shown below. A dip at 120 Hz is probably due to line noise. We are also assuming that the oplev QPDs have a relatively flat response over the frequency range below.

Attachment 1: PRM_PIT_ACT_TF.pdf  7 kB  Uploaded Mon Sep 20 13:27:08 2021  | Hide | Hide all
PRM_PIT_ACT_TF.pdf
Attachment 2: PRM_YAW_ACT_TF.pdf  7 kB  Uploaded Mon Sep 20 13:27:22 2021  | Hide | Hide all
PRM_YAW_ACT_TF.pdf
Attachment 3: BS_PIT_ACT_TF.pdf  7 kB  Uploaded Mon Sep 20 13:27:28 2021  | Hide | Hide all
BS_PIT_ACT_TF.pdf
Attachment 4: BS_YAW_ACT_TF.pdf  7 kB  Uploaded Mon Sep 20 13:27:38 2021  | Hide | Hide all
BS_YAW_ACT_TF.pdf
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