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Entry  Sun Sep 4 18:43:55 2016, awade, DailyProgress, DAQ, Setting up PID slow controls for FSS, issues with fb2 on restart 100_0203.JPG
    Reply  Mon Sep 5 18:37:16 2016, awade, DailyProgress, DAQ, Setting up PID slow controls for FSS, issues with fb2 on restart 
       Reply  Wed Sep 7 13:03:56 2016, awade, DailyProgress, DAQ, Setting up PID slow controls for FSS (South path) SLOW_PID.plScreen_Shot_2016-09-07_at_12.46.47_PM.pngScreen_Shot_2016-09-07_at_12.52.44_PM.pngScreen_Shot_2016-09-07_at_12.58.05_PM.png
          Reply  Fri Sep 23 17:21:02 2016, awade, DailyProgress, DAQ, Setting up PID slow controls for FSS 100_0210.JPG
             Reply  Mon Oct 3 18:10:26 2016, rana, DailyProgress, TempCtrl, Setting up PID slow controls for FSS 
                Reply  Tue Oct 4 11:08:27 2016, awade, DailyProgress, TempCtrl, Setting up PID slow controls for FSS 
Message ID: 1731     Entry time: Mon Oct 3 18:10:26 2016     In reply to: 1722     Reply to this: 1733
Author: rana 
Type: DailyProgress 
Category: TempCtrl 
Subject: Setting up PID slow controls for FSS 

Depends on the series resistance of the slow input. Maybe that's in the manual? The response of the SLOW input can be measured by driving this input and looking at the FAST voltage while the cavity is locked. Its roughly 1 GHz/V for the SLOW input and 5 MHz/V for the FAST, so the SLOW should only be driven by a ~1 mV signal. There is a thermal constant which makes the FAST/SLOW crossover stable, but you should put in a low pass filter with ~2 poles below 10 Hz to remove the high frequency junk getting in there.

Quote:

This should be fine I guess for cutting out ripple voltage. Am I missing something or do we want a more typical LP filter like an RC circuit to operate with a (say) 10 Hz cut off.  I'm not sure of the design motivations.

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