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<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy">Hi Andreas,<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy">Thanks for your reply.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy">Which document page no 27 you are referring? May you send me that document or location of same?<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy">Regards,<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="navy" face="Arial"><span style="font-size:
10.0pt;font-family:Arial;color:navy">Yogesh<o:p></o:p></span></font></p>
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10.0pt;font-family:Arial;color:navy"><o:p> </o:p></span></font></p>
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<p class="MsoNormal"><b><font size="2" color="black" face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma;color:windowtext;font-weight:bold">From:</span></font></b><font size="2" color="black" face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma;
color:windowtext">
etherlab-users-bounces@etherlab.org [mailto:etherlab-users-bounces@etherlab.org]
<b><span style="font-weight:bold">On Behalf Of </span></b>Andreas Stewering-Bone<br>
<b><span style="font-weight:bold">Sent:</span></b> Thursday, May 19, 2011 12:46 PM<br>
<b><span style="font-weight:bold">To:</span></b> <st1:PersonName w:st="on">etherlab-users@etherlab.org</st1:PersonName><br>
<b><span style="font-weight:bold">Subject:</span></b> Re: [etherlab-users] [PATNI] Regarding DC Synchronisation</span></font><font color="black"><span style="color:windowtext"><o:p></o:p></span></font></p>
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<p class="MsoNormal"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">Hello Yogesh,<br>
<br>
you have to notice following steps:<br>
<br>
- If you want to do DC, you have to use a RT-kernel and a RT-application, because jitter on the base system can be a sync problem.<br>
<br>
- Do not use NTP on the system, use CLOCK_MONOTONIC or CLOCK_MONOTONIC_RAW if accessible to get a stable clocksource.<br>
<br>
- Get system time just before you set the application time, to get the correct time.<br>
<br>
- Sync slaves every transmit cycle.<br>
<br>
- Rise up the cycle freq, the DC syncs better if you have faster transmit cycles<br>
<br>
- your second question: see doc under page 27- > watch -n0 "ethercat reg read -p4 -tsm32 0x92c"<br>
<br>
<br>
<br>
Best regards<br>
<br>
Andreas<br>
<br>
Am 19.05.2011 08:59, schrieb <st1:PersonName w:st="on">Dhake, Yogesh</st1:PersonName>:
<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt"><u1:p> </u1:p><o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" color="black" face="Arial"><span style="font-size:
10.0pt;font-family:Arial">Hi</span></font><font size="2" color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy">,<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal"><font size="2" color="black" face="Arial"><span style="font-size:
10.0pt;font-family:Arial">EtherCAT master performs DC synchronization as below:<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Initially EtherCAT master calculates Propagation delay time between slaves.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Time Delay calculated (actual frame send from Master state machine - application start time) and deducted
from System Time read from slave. New Offset time (new offset = old offset from slave + time difference between Master Application Start Time and Slave System Time) is send to slaves.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">After this, Master sends synchronization datagram (with command FRMW-First READ MULTIPLE WRITE) to reference
clock slave as well as to other EtherCAT slaves on network.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">FRMW command reads reference clock slave system time (lower 32 bit) (0x0910 to 0x0927) and writes to
lower 32 bit of other EtherCAT slave system time register (0x0910 to 0x0927).<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Activity number 2 to 4 happens at every 10ms in user application.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Our observation is difference between master time and slave system time is around 16-20 seconds after
step 2.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Slave System Time is not accessible to us for checking whether Slave System Time synchronized with Master
Application Time. <u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial"><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial"><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Our query is:<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:1.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">How can we reduce difference between Master Application Time and Slave System Time in step 2?<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:1.5in;text-indent:-.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">How to check System Time register of BECKHOFF slave after step 4?<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal"><font size="2" color="black" face="Arial"><span style="font-size:
10.0pt;font-family:Arial"><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Please let us know your valuable inputs regarding synchronization of Distributed clocks of EtherCAT slaves.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial"><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Please find attached DC synchronization process. Rename file to .png type.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial"><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Regards,<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.25in"><font size="2" color="black" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Yogesh<u1:p></u1:p></span></font><o:p></o:p></p>
<p class="MsoNormal"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt"><o:p> </o:p></span></font></p>
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<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"> <o:p></o:p></span></font></pre>
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<br>
<br>
<o:p></o:p></span></font></p>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Mit freundlichem Gruß<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"><o:p> </o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Andreas Stewering-Bone<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"><o:p> </o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">-- <o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">------------------------------------------------------------------------<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"><o:p> </o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Dipl.-Ing.(FH) Andreas Stewering-Bone<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"><a href="mailto:andreas.stewering-bone@igh-essen.com">andreas.stewering-bone@igh-essen.com</a><o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Tel.: +49 201 / 36014-15<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"><o:p> </o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Ingenieurgemeinschaft IgH<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Gesellschaft für Ingenieurleistungen mbH<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Heinz-Bäcker-Str. 34<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">D-45356 <st1:City w:st="on"><st1:place w:st="on">Essen</st1:place></st1:City><o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Amtsgericht Essen HRB 11500<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">USt-Id.-Nr.: DE 174 626 722<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Geschäftsführung: <o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">- Dr.-Ing. S. Rotthäuser, <o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">- Dr.-Ing. T. Finke, <o:p></o:p></span></font></pre>
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<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">Tel.: +49 201 / 360-14-0<o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"><a href="http://www.igh-essen.com">http://www.igh-essen.com</a><o:p></o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt"><o:p> </o:p></span></font></pre>
<pre><font size="2" color="black" face="Courier New"><span style="font-size:10.0pt">------------------------------------------------------------------------<o:p></o:p></span></font></pre>
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