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</style><article id="node-600271" class="node node-logentry article ia-n clearfix" role="article"><header class="node-header"><h1 class="node-title">
<a href="https://logbooks.jlab.org/entry/3527396" rel="bookmark">Torus Helium Level Control</a>
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<p class="author-datetime">
Lognumber <a href="https://logbooks.jlab.org/entry/3527396" class="lognumber" data-lognumber="3527396">3527396</a>. Submitted by <a href="https://logbooks.jlab.org/user/kashy">kashy</a> on <time datetime="2018-02-05T09:30:58-0500" pubdate="pubdate">Mon, 02/05/2018 - 09:30</time>. </p>
<table class="field-vitals"><tr><th>Logbooks: </th><td><a href="https://logbooks.jlab.org/book/hblog">HBLOG</a> <a href="https://logbooks.jlab.org/book/hbsolenoid">HBSOLENOID</a> <a href="https://logbooks.jlab.org/book/hbtorus">HBTORUS</a></td></tr></table></div>
<div class="logentry node-content">
<p>Sunday afternoon and early this morning the Helium level in the Torus fell below the controlled ramp down value. The last time this happened it was conincedent with issues with the Buffer Dewar IOC. I did not make any changes at that time as it was not clear that we had an issue that a warranted a control change.</p>
<p> It seems the root cause for the Torus helium level drops this time was a warm helium burp out of the Solenoid.<br />
To address this I made changes to allow the Torus to react sooner as well as action to limit the duration of a warm bump out of the Solenoid.</p>
<p>I I changed the following sepoints on the 3 control loops that control its level<br />
HTR8120 Set value 85 ->90%<br />
EV8115JT Set value 72 ->80%<br />
EV8111CD 67-> 75% </p>
<p>I also changed some gains on HTR8120 to slow it down<br />
Max chg 10 -> 3<br />
Sample time 30 -> 10<br />
P Gain -15 -> -5<br />
I gain -0.05 -> -0.15</p>
<p>Finally I changed the PID for EV8611JT_Min<br />
Max Pos 65 -> 73<br />
Max change 0.3 -> 1.0</p>
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<div class="image-wrapper"><img view_mode="elog_email" class="image-style-plentybig" src="cid:5453dd533ea8254f7e58844b8f54ce02@logbooks.jlab.org" width="431" height="894" alt="" title="New setup for HTR8120" /></div> <div class="image-wrapper"><img view_mode="elog_email" class="image-style-plentybig" src="cid:ee6cd33e6b45aeb3d3e615c831d775fe@logbooks.jlab.org" width="960" height="676" alt="" title="New Setup for EV8115JT" /></div> <div class="image-wrapper"><img view_mode="elog_email" class="image-style-plentybig" src="cid:aa80fa1f7e5c11f85341228b190b93f0@logbooks.jlab.org" width="841" height="874" alt="" title="New Setup for EV8111CD" /></div> <div class="image-wrapper"><img view_mode="elog_email" class="image-style-plentybig" src="cid:39638481e16aaabee739846773ee9e62@logbooks.jlab.org" width="841" height="874" alt="" title="New Setup for EV8611JT_Min" /></div> </div>
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