40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  PSL  Not logged in ELOG logo
Entry  Tue Jun 15 09:44:56 2010, tarac, Electronics, , PMC servo TF  PMC2_bode.pngnotch_bode.pngPMC2_bode.png
    Reply  Tue Jun 15 10:14:32 2010, Frank, Electronics, , PMC servo TF  
Message ID: 161     Entry time: Tue Jun 15 09:44:56 2010     Reply to this: 162
Author: tarac 
Type: Electronics 
Subject: PMC servo TF  

   The weird TF result from PMC seems to be the result of the insufficient voltage input. When I increased the swept sine voltage from 2mV to 500 mV, the result of the TF becomes as expected. See fig 1.

    Before the signal is fed back to PMC, there is a PMC notch box. It is a low pass filter. It's TF looks fine (fig.2.)

However, when the TF of the servo and the notch is measured together, they look shaky.

I just read Frank's comment. I'll check the schematic of the PMC servo again.

Attachment 1: PMC2_bode.png  16 kB  | Hide | Hide all
Attachment 2: notch_bode.png  11 kB  Uploaded Tue Jun 15 11:26:01 2010  | Hide | Hide all
Attachment 3: PMC2_bode.png  25 kB  Uploaded Tue Jun 15 11:26:58 2010  | Hide | Hide all
ELOG V3.1.3-