<html><body><div style="font-family: tahoma,new york,times,serif; font-size: 14pt; color: #009900"><div>thanks brian.<br></div><div><br data-mce-bogus="1"></div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"Brian Eng" <beng@jlab.org><br><b>To: </b>"Amrit Yegneswaran" <yeg@jlab.org><br><b>Cc: </b>"dsg-hallb magnets" <dsg-hallb_magnets@jlab.org><br><b>Sent: </b>Friday, October 14, 2016 12:27:57 PM<br><b>Subject: </b>Re: [Dsg-hallb_magnets] cernox sensor issue<br></div><div><br></div><div data-marker="__QUOTED_TEXT__">Instead of explaining with text, which could be confusing, I've attached a few screenshots of the various VI block diagrams.<div class=""><br class=""></div><div class="">For reference here's a PDF for the algorithm: M:\hallb_eng\CLAS12\Magnets\Torus\JLab Torus\C&I_Torus\Controls_&_Wiring\Fast DAQ\Cernox Algorithm\TR Algorithm.pdf</div><div class=""><br class=""></div><div class="">Here's what the VI looks like now (attached as current.png):</div><div class=""><br class=""></div><div class=""><img id="0C0319D7-0C88-4621-B1D6-353833916B27" src="cid:7F0F14F1-4E0D-4436-96CA-5D778782FCED@jlab.org" class="" data-mce-src="cid:7F0F14F1-4E0D-4436-96CA-5D778782FCED@jlab.org" height="409" width="590"></div><div class=""><br class=""></div><div class="">The issue I've found with the current algorithm is that it will increase the current as the temperature increases, but it won't decrease the current as it goes down.</div><div class=""><br class=""></div><div class="">After noticing that the logic doesn't exactly match the reference algorithm (namely the additional checks on power dissipation) I modified the VI to look like the following (attached as updated.png):</div><div class=""><br class=""></div><div class=""><img id="19191C65-11E8-47B9-9EA7-EE00895C906F" src="cid:B0222BB1-8A4F-4061-9E5C-00025DDAF1B7@jlab.org" class="" data-mce-src="cid:B0222BB1-8A4F-4061-9E5C-00025DDAF1B7@jlab.org" height="364" width="588"></div><div class=""><br class=""></div><div class="">This version properly increased and decreased the current with my admittedly limited testing of using a single potentiometer in place of a cernox sensor and varying it up and down between 4K and 325K.</div><div class=""><br class=""></div><div class="">Finally I removed some of the terminals that weren't being used and changed the code to use more LabVIEW primitives in my process of upgrading to 2016 (attached as simplified.png):</div><div class=""><br class=""></div><div class=""><img id="63DBAD13-037A-4AB8-8C5C-CB7F8E129CD5" src="cid:7AE74E06-36D1-483B-9273-1CEF48CA097C@jlab.org" class="" data-mce-src="cid:7AE74E06-36D1-483B-9273-1CEF48CA097C@jlab.org" height="208" width="577"></div><div class="">Hopefully the images make sense and get sent through to the mailing list okay.</div><div class=""><br class=""><div class="">--<br class="">Brian Eng<br class="">Detector Support Group<br class="">757-269-6018</div><br class=""><blockquote class="">On Oct 12, 2016, at 6:44 PM, Amrit Yegneswaran <<a href="mailto:yeg@jlab.org" class="" target="_blank" data-mce-href="mailto:yeg@jlab.org">yeg@jlab.org</a>> wrote:<br class=""><br class="">hello brian,<br class=""><br class="">today you and i had a discussion about the cernox sensor problem.<br class="">at the dsg meeting we further discussed the matter.<br class="">you mentioned that there were some errors in the main program VIs, which i'vent seen.<br class="">when you mentioned that you had e-mailed christians (author of the code) and nick i mentioned you to post a few words regarding this issue, so that rather than a select few, all of us including i might be aware of the source and cure.<br class="">perhaps it slipped your mind that i requested you the source and the cure for the problem.<br class="">i am documenting all these issues so that newcomers like pablo and tyler understand these issues and can provide <br class="">effective support.<br class=""><br class="">so when you come back on friday please do so.<br class="">amrit</blockquote></div><br></div></div></body></html>