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Entry  Fri Jul 20 12:12:25 2012, rana, Update, PSL, PMC problems examined Untitled.png
    Reply  Sat Jul 21 14:05:21 2012, Den, Update, PSL, PMC problems examined fss_slowm.png
Message ID: 6995     Entry time: Fri Jul 20 12:12:25 2012     Reply to this: 6998
Author: rana 
Type: Update 
Category: PSL 
Subject: PMC problems examined 

Jenne, Den, Rana

The PMC transmission has been varying a lot and the MC seems unstable. Superstitious people might blame this on the El-nino or the alignment with Sagitarius, but we are ostensibly scientists.

WE found that the PMC EPICS values had not been toggled since the reboot and so the RF phase and Amplitude were totally wrong (we should replace this with a fixed oscillator box as we did with FSS).

Also, the NPRO SLOW slider was at -2 V which made the mode going into the PMC funny (although the mode was OK this morning before I started playing with the PMC sliders).

Before adjustment, there was a strong correlation between the seismic motions and the PMC reflection. This means that the PMC gain was low and it couldn't stay locked. Now, after fixing the RF and upping the gain slider it looks more stable. Let's watch it for a few days to see if there's an improvement in the trends.

The 10-minute trend of the lat 400 days shows that nothing has changed much this year; its been equally bad for a long while.

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