<div dir="ltr"><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">---------- Forwarded message ---------<br>From: <strong class="gmail_sendername" dir="auto">Julius Madey</strong> <span dir="auto"><<a href="mailto:hillfox@fairpoint.net" target="_blank">hillfox@fairpoint.net</a>></span><br>Date: Tue, Jul 28, 2020 at 8:13 PM<br>Subject: Re: How do you feel about my forwarding your results to other users?<br>To: David Witten <<a href="mailto:wittend@wwrinc.com" target="_blank">wittend@wwrinc.com</a>><br></div><br><br>
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<font face="Arial">Dave.<br><br>
</font></div><div><font face="Arial">Here's the first couple of pieces on temp sensitivity.
Considering the full range of the RM3100, the observed effect
could be considered relatively small. However, it's in the region
we need to observe. Although the basic idea of taking the
differences in duty cycle of the LR oscillator with forward and
reverse bias eliminates some major temperature contributions, it
apparently does not totally eliminate them.<br>
<br>
One is of a GTJ run on 07072020 and the other a one hour
calibration run I did yesterday 07272020. Note the reversed sense
of the temperature change effect. I have a second RM3100 which I
will also run in the next few days for comparison. I used your
original adapter board. The setup in the wood lot at the end of
400 feet of CAT5E I believe uses the same adapter board you
supplied to Hyomin. Reducing the 24 hour data in Open Office Calc
took a god-awful time to complete.<br>
<br>
Feel free to distribute these ... I'm going to send them to PNI
for their comment. I did not attempt to measure the drift, if
any, of the 3.3 volt regulator output on the SparkFun i2c
differential extender at the test end. I also have data which was
taken with a delay between the start command and looking at the
Status register to keep the i2c bus quiet during measurement and
the trends are the same. I don't think PC trace currents created
that much local field but that's another check for the future.<br>
<br>
Jules<br>
<br></font><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="gmail-gs" style="margin:0px;padding:0px 0px 20px;width:1503px;font-family:Roboto,RobotoDraft,Helvetica,Arial,sans-serif;font-size:medium"><div class="gmail-gE gmail-iv gmail-gt" style="padding:20px 0px 0px;font-size:0.875rem"><br class="gmail-Apple-interchange-newline"><table cellpadding="0" class="gmail-cf gmail-gJ" style="border-collapse:collapse;margin-top:0px;width:auto;font-size:0.875rem;letter-spacing:0.2px;display:block"><tbody style="display:block"><tr class="gmail-acZ" style="height:auto;display:flex"><td class="gmail-gF gmail-gK" style="white-space:nowrap;padding:0px;vertical-align:top;width:1199.91px;line-height:20px;display:block;max-height:20px"><table cellpadding="0" class="gmail-cf gmail-ix" style="border-collapse:collapse;table-layout:fixed;width:1199px"><tbody><tr><td class="gmail-c2" style="display:flex"><h3 class="gmail-iw" style="overflow:hidden;font-size:0.75rem;font-weight:inherit;margin:inherit;text-overflow:ellipsis;letter-spacing:0.3px;color:rgb(95,99,104);line-height:20px"><span class="gmail-qu" tabindex="-1"><span name="Julius Madey" class="gmail-gD" style="color:rgb(32,33,36);font-size:0.875rem;font-weight:bold;display:inline;vertical-align:top;letter-spacing:0.2px;line-height:20px">Julius Madey</span></span></h3></td></tr></tbody></table></td><td class="gmail-gH gmail-bAk" style="text-align:right;white-space:nowrap;vertical-align:top;display:block;max-height:20px"><div class="gmail-gK" style="padding:0px;display:flex"><img class="gmail-f gmail-gW" src="https://mail.google.com/mail/u/0/images/cleardot.gif" title="RM3100 Not Affected by Temperature Change – PNI Sensor Help Center.pdf" alt="Attachments" style="vertical-align: top; background: url("https://www.gstatic.com/images/icons/material/system/1x/attachment_black_20dp.png") 50% 50% / 20px no-repeat; height: 20px; width: 20px; opacity: 0.54;"><span id="gmail-:pn" class="gmail-g3" title="Jul 28, 2020, 11:15 AM" alt="Jul 28, 2020, 11:15 AM" tabindex="-1" style="vertical-align:top;margin:0px;font-size:0.75rem;letter-spacing:0.3px;color:rgb(95,99,104);display:block;line-height:20px">Tue, Jul 28, 11:15 AM (21 hours ago)</span><div class="gmail-zd gmail-bi4" title="Not starred" tabindex="0" style="display:inline-block;height:20px;margin-left:20px;outline:0px"><span class="gmail-T-KT" style="display:inline-flex;height:20px;text-align:center;width:20px;padding:0px;margin:0px;border:none;outline:none"></span></div></div></td><td class="gmail-gH" style="text-align:right;white-space:nowrap;vertical-align:top;display:flex"></td><td class="gmail-gH gmail-acX gmail-bAm" rowspan="2" style="text-align:right;white-space:nowrap;vertical-align:top;display:block;max-height:20px"><div class="gmail-T-I gmail-J-J5-Ji gmail-T-I-Js-IF gmail-aaq gmail-T-I-ax7 gmail-L3" tabindex="0" style="display:inline-flex;border-radius:2px 0px 0px 2px;font-size:0.875rem;text-align:center;margin:0px 0px 0px 20px;height:20px;line-height:18px;min-width:0px;outline:none;padding:0px;background:transparent;color:rgb(68,68,68);border:none"><img class="gmail-hB gmail-T-I-J3" src="https://mail.google.com/mail/u/0/images/cleardot.gif" alt="" style="background: url("https://www.gstatic.com/images/icons/material/system/1x/reply_black_20dp.png") 50% 50% / 20px no-repeat; 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cursor: pointer; padding: 0px; vertical-align: baseline; height: 20px; width: 20px; border: none; margin: 0px 0px 0px auto; right: 0px; top: 0px; display: flex; opacity: 0.54;"></div></td></tr></tbody></table></td></tr></tbody></table></div><div id="gmail-:sj"><div class="gmail-qQVYZb"></div><div class="gmail-utdU2e"></div><div class="gmail-lQs8Hd"></div><div class="gmail-btm"></div></div><div class="gmail-"><div class="gmail-aHl" style=""></div><div id="gmail-:151" tabindex="-1"></div><div id="gmail-:si" class="gmail-ii gmail-gt gmail-adO" style="font-size:0.875rem;direction:ltr;margin:8px 0px 0px;padding:0px"><div id="gmail-:152" class="gmail-a3s gmail-aXjCH" style="overflow:hidden;font-variant-numeric:normal;font-variant-east-asian:normal;font-stretch:normal;font-size:small;line-height:1.5;font-family:Arial,Helvetica,sans-serif"><div class="gmail-adM"></div><div><div class="gmail-adM"></div><font face="Arial">Dave,<br>I have no problem with sharing that my tests so far have shown that, at least on the y axis which was tested, the RM3100 is well within 5% accuracy with Helmholtz coil excitation with a long period (30 minutes to 1 hour) sine wave of +/-50, +/- 524 and +/- 2893 nT. And I would be happy to provide graphs to the repository.<br><br>My problem at this point is incomplete data on another aspect, which is why I haven't released the stuff I mentioned yesterday.<br><br>PNI claims that the basic measurement technique employed in the RM3100 eliminates temperature effects. See the attached note.<br><br>However, I am clearly seeing what appear to be temperature related effects in the measurements, at least at lower levels like 30 to 150nT variations of the sort seen at the Jenny Jump tests. If you know the tempco, it's possible to compensate in the data reduction ..... however......the disconcerting thing is that I'm seeing different trends vs temp in the GTJ results and the runs I did in the last couple of days. Tempco sign differences, which suggests magnetometers may have to be calibrated before deployment ... temperature variations of 15 C or more<br><br>If I look at the temperature related effects of the GTJ measurements (tedious work due to the large data set) it appears that the significant deviation which Hyomin noted between the GTJ and JJ data is entirely due to temperature variations over the 24 hour runs !!<br><br><br></font>I have an inquiry in to PMI.<br><br>Jules<div class="gmail-yj6qo gmail-ajU" style="outline:none;padding:10px 0px;width:22px;margin:2px 0px 0px"><div id="gmail-:om" class="gmail-ajR" tabindex="0" style="background-color:rgb(232,234,237);border:none;clear:both;line-height:6px;outline:none;width:24px;border-radius:5.5px"><img class="gmail-ajT" src="https://ssl.gstatic.com/ui/v1/icons/mail/images/cleardot.gif" style="background: url("https://www.gstatic.com/images/icons/material/system/1x/more_horiz_black_20dp.png") 50% 50% / 20px no-repeat; height: 11px; opacity: 0.7; width: 24px;"></div></div></div></div></div><div class="gmail-hq gmail-gt gmail-a10" id="gmail-:sf" style="margin:15px 0px;clear:both;font-size:0.875rem"><div class="gmail-hp" style="width:1503px;border-top:1px dotted rgb(216,216,216)"></div><div class="gmail-a3I" style="width:1px;height:1px;overflow:hidden">Attachments area</div><div id="gmail-:pq"></div><div class="gmail-aQH" id="gmail-:pp" style="padding-top:16px"><div class="gmail-aZK" style="height:0px;overflow:hidden;clear:both"></div></div></div><div class="gmail-hi" style="border-bottom-left-radius:1px;border-bottom-right-radius:1px;padding:0px;width:auto;background:rgb(242,242,242);margin:0px"></div></div></div><br class="gmail-Apple-interchange-newline"></blockquote>
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