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<font face="Helvetica, Arial, sans-serif">I think yes we should do
this.</font><br>
<br>
<div class="moz-cite-prefix">On 09/04/2018 09:36 AM, Timothy
Whitlatch wrote:<br>
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<div>Hi Brian,<br>
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<div><br data-mce-bogus="1">
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<div>We will have time this week to reboot the PXI (Just not
today).<br data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
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<div>Hovanes and Beni, do you think we should implement the fix
this week?<br data-mce-bogus="1">
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<div data-marker="__SIG_PRE__">Tim Whitlatch<br>
Hall D Engineer<br>
Jefferson Lab<br>
600 KELVIN DR STE 5<br>
Newport News, VA 23606-4468 <br>
757-269-5087</div>
<div><br>
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<hr id="zwchr" data-marker="__DIVIDER__">
<div data-marker="__HEADERS__"><b>From: </b>"Brian Eng"
<a class="moz-txt-link-rfc2396E" href="mailto:beng@jlab.org"><beng@jlab.org></a><br>
<b>To: </b>"Hall D Controls" <a class="moz-txt-link-rfc2396E" href="mailto:halld-controls@jlab.org"><halld-controls@jlab.org></a><br>
<b>Sent: </b>Thursday, August 30, 2018 1:46:47 PM<br>
<b>Subject: </b>[Halld-controls] PXI Time Stamps<br>
</div>
<div><br>
</div>
<div data-marker="__QUOTED_TEXT__">We recently discovered that
the time used by the PLCs has a offset to it which causes them
to use/provide an incorrect time.<br>
<br>
It manifests itself in 2 ways:<br>
1) If the CC server is the master the PLC will be 34 seconds
fast<br>
2) if the PLC is the master any devices on the same subnet
will be 34 seconds fast<br>
<br>
That 34 seconds is hard-coded in the PLC ethernet module and
only changed by upgrading the firmware (but it still won't be
user adjustable). It comes from the offset between UTC &
TAI time when the module was purchased.<br>
<br>
Currently we're operating in the second configuration.<br>
<br>
There is an option to correct this offset with Linux based NI
devices, but I haven't yet tested it with the other OSes
(namely the PXI which uses Phar Lap).<br>
<br>
Unfortunately even if I can remove this offset it will require
rebooting the PXI, so my question is should I try pursuing
fixing this or is knowing that there is a fixed & constant
offset good enough for now?<br>
<br>
<br>
<br>
<br>
P.S. This isn't like the earlier time problems we had where
the time would slowly wander off, this is a fixed value with
only the error of PTP coming into play which should be at the
sub-ms level.<br>
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