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Entry  Mon Oct 15 08:12:45 2012, Steve, Update, VAC, blank vac monitor blankvac.png
    Reply  Mon Oct 15 13:07:51 2012, jamie, Update, VAC, vacuum VME crate broken, replaced, minor vacuum mayhem ensues 
       Reply  Mon Oct 15 14:51:16 2012, Jenne, Update, SUS, SUS were kicked hard as a result 
          Reply  Mon Oct 15 17:08:01 2012, Steve, Update, VAC, vacuum is back with some disabled valves VMEcrateout.pngIMG_1725.JPGwarning.pngshortcomings.jpg
             Reply  Wed Oct 24 09:15:12 2012, Steve, Update, VAC, vacuum rack 24V ps was current limited currentlimited24V.jpg
                Reply  Mon Nov 5 10:34:48 2012, Steve, Update, VAC, existing vacuum documents 
                Reply  Fri Aug 16 09:35:18 2013, Steve, Update, VAC, Vacuum Normal state recognition is back VacuumNormal.pngvacValvesDisabled.jpg
Message ID: 7549     Entry time: Mon Oct 15 17:08:01 2012     In reply to: 7548     Reply to this: 7605
Author: Steve 
Type: Update 
Category: VAC 
Subject: vacuum is back with some disabled valves 

Quote:

Quote:

Apparently all of the ION pump valves (VIPEE, VIPEV, VIPSV, VIPSE) opened, which vented the main volume up to 62 mTorr.  All of the annulus valves (VAVSE, VAVSV, VAVBS, VAVEV, VAVEE) also appeared to be open.  One of the roughing pumps was also turned on.  Other stuff we didn't notice?  Bad. 

 Several of the suspensions were kicked pretty hard (600+ mV on some sensors) as a result of this quick vent wind.  All of the suspensions are damped now, so it doesn't look like we suffered any damage to suspensions.

CLOSE CALL on the vacuum system:

Jamie and I disabled V1, VM2 and VM3 gate valves by disconnecting their 120V solenoid actuator before the swap of the VME crate.

The vacuum controller unexpectedly lost control over the swap as Jamie described it. We were lucky not to do any damage! The ion pumps were cold and clean. We have not used them for years so their outgassing possibly  accumulated to reach ~10-50 Torr

I disconnected_ immobilized and labelled the following 6 valves:  the 4 large ion pump gate valves and VC1,  VC2  of the cryo pump. Note: the valves on the cryo pump stayed closed. It is crucial that a warm cry pump is kept closed!

This will not allow the same thing to happen again and protect the IFO from warm cryo contamination.

The down side of this that the computer can not identify vacuum states any longer.

This vacuum system badly needs an upgrade. I will make a list.

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Attachment 3: warning.png  241 kB  Uploaded Wed Oct 17 09:15:50 2012  | Hide | Hide all
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Attachment 4: shortcomings.jpg  255 kB  Uploaded Fri Nov 2 18:04:53 2012  | Hide | Hide all
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