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Entry  Fri Oct 9 11:41:09 2015, ericq, Update, VAC, N2 Pressure fell 
    Reply  Fri Oct 16 18:27:52 2015, Steve, Update, VAC, vacuum normal condition oct16Fpm2015.png
       Reply  Tue Oct 20 16:27:04 2015, ericq, Update, VAC, vacuum VME machines rebooted 
          Reply  Wed Oct 21 10:03:15 2015, Steve, Update, VAC, after running out of N2 1d_after_reboot.png
             Reply  Wed Oct 21 15:42:56 2015, Steve, Update, VAC, vacuum gauge check Gauges.png
                Reply  Tue Oct 27 10:08:12 2015, Steve, Update, VAC, CC vacuum gauges gauges_5y_vs_8d.png13.9yCC1&4.png
                   Reply  Mon Dec 7 11:17:51 2015, Steve, Update, VAC, noisy RGA scan at day 433 433dRGAscan.png
                      Reply  Tue Dec 8 15:40:48 2015, Steve, Update, VAC, glitchy RGA scan at day 434 lessGlichingToday.png
                         Reply  Wed Dec 9 11:25:55 2015, Steve, Update, VAC, normal RGA scan at day 435-436 glichesGone.pngd436.png
                            Reply  Fri Jan 29 09:59:23 2016, Steve, Update, VAC, vacuum control upgrade 1100days.png
             Reply  Thu Oct 22 08:52:04 2015, Steve, Update, VAC, clean RGA scan after sweaty Maglev clean_scan.png
          Reply  Fri Sep 30 10:37:57 2016, Steve, Update, VAC, vacuum VME machines rebooted rebooted.png
Message ID: 11705     Entry time: Wed Oct 21 10:03:15 2015     In reply to: 11703     Reply to this: 11706   11707
Author: Steve 
Type: Update 
Category: VAC 
Subject: after running out of N2 

 

Quote:

[ericq, Gautam, Steve]

Following roughly the same procedure as ELOG 11354, c1vac1 and c1vac2 were rebooted. The symptoms were identical to the situation in that ELOG; c1vac1 could be pinged and telneted to, but c1vac2 was totally unresponsive. 

The only change in the linked procedure was that we did not shut down the maglev. Since I unwittingly had it running for days without V4 open while Steve was away, we now know that it can handle shorter periods of time than that...

Upon reboot, many channels were readable again, unfortunately the channels for TP2 and TP3 are still blank. We were able to return to "Vacuum normal state," but because of unknowned communication problems with VM1's interlock, we can't open VM1 for the RGA. Instead we opened VM2 to expose the RGA to the main IFO volumn, but this isn't part of the "Normal" state definite, so things currently read "Undefined state".

Precondition:

1, Pressure gauges had no communication ( NO COMM ) with c1vac2

 

2, Lost N2 supply on Oct 9 This triggered a normal all valve closed condition. At this point you replace N2 cylinders and manually swich valves to recreate VAC NORMAL configuration in the correct sequential order.

   The very last thing you do is open V1 gate valve.

   a, check TP2 that is the forepump of the Maglev. Foreline pressure to drypump  ~ 10- 100 mTorr, rotation speed 50 Krpm

   b, open V4 if P2 <1Torr

   c, check Maglev rotating at 560 Hz

   d, open V1 if P1 <500 mTorr

   e, check TP3 foreline, rotation speed and open V5 if P3 <1 Torr with VA6 closed

   f, open VA6 if PAN <1 Torr

  g, open annulos valves one by one , like VASE if PASE <1 Torr and so on...........Now the Current State: should read Vac Normal

 

3, Maglev run for 7 days with V4 closed. This encreased its foreline pressure to estimated few Torrs  and its body temp rose ~30C on the outside.

   So it was sweating and it may be back streamed.

The present RGA data is indicating that it had to be very mild.

The RGA will have better sensitivity with VM1 open and VM2 closed.

The PSL output shutter stayed open during these period is pointing  to IFO pressure stayed P1 <3 mTorr

PROBLEM: P1 and P2 plot should show nothing where there is no communication.http://nodus.ligo.caltech.edu:8080/40m/151016_182003/oct16Fpm2015.png

                   How do we check if pressure based software interlocks are working in this no communication condition?

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