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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The “system_time_base less than system time” is from the rtai_rtdm_dc example code.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">In the example it looks like system_time_base is initialised to zero and adjusted by a maximum of +-1001 each cycle. A value of -58905492552780 indicates that
system_time_base is not being correctly initialised or is being corrupted with any other values.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">As to the motor “knock” every now and then, this is due to the motors dc clock not being correctly synchronized with the masters cycle time. It is due to the
master either missing or sending two messages to the amps in one cycle every now and then. Sort out your dc timing and the knock will go away.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Graeme.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext"> etherlab-users [<a href="mailto:etherlab-users-bounces@etherlab.org">mailto:etherlab-users-bounces@etherlab.org</a>]
<b>On Behalf Of </b>Bilko AS, Oguz Dilmac<br>
<b>Sent:</b> Tuesday, 26 January 2016 4:37 a.m.<br>
<b>To:</b> <a href="mailto:etherlab-users@etherlab.org">etherlab-users@etherlab.org</a><br>
<b>Subject:</b> [etherlab-users] rtai_rtdm_dc example, "error: system_time_base less than system time" message<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hi,<br>
<br>
We have been using EtherCAT master 1.5.2 for about two years. We have successfully implemented 4 machines. Each has 5 Kollmorgen AKD servo drives and some Beckhoff IO modules.<br>
Now we are implementing a new machine. On this machine we usually get the following messages:
<br>
...<br>
"system2count() error: system_time_base less than system time (system_time_base: -58905492552780, time:680659495658"<br>
"system2count() error: system_time_base less than system time (system_time_base: -58905492552858, time:680660495658"<br>
"system2count() error: system_time_base less than system time (system_time_base: -58905492552936, time:680661495658"<br>
"system2count() error: system_time_base less than system time (system_time_base: -58905492553014, time:680662495658"<br>
...<br>
<br>
We implemented our system based on the <b>rtai_rtdm_dc</b> example. Only main difference is, we use kernel modules with RTAI instead of LXRT user mod.<br>
We are using "cyclic positon" (8) mode with distributed clock. <br>
We choose the first DC capable device as the reference clock by calling <b>ecrt_master_select_reference_clock(master, 0);<br>
</b>The first node on the bus is a AKD servo drive.<br>
<br>
The error occurs from the startup and not disappear until we reboot the PC and the drives.
<br>
When the error occurs, it seems sometimes drives can't update the new position reference. Therefore, if it is moving, it tries to stop for one sample and continues to the new reference at the next sample.
<br>
This causes a loud "knock" sound on the machine.<br>
<br>
We didn't get this message with previous 4 machines. <br>
We tried different FW versions of the AKD drives. Also tried to change the bus node order of the drives. But nothing changed.<br>
Do you know what can be the cause for this message? How can we fix the problem?<br>
<br>
Best regards,<br>
Oguz.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">-- <br>
<br>
<o:p></o:p></p>
<pre>Oguz Dilmac<o:p></o:p></pre>
<pre>ARGE Bolumu<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>Bilko AS, R&D Department<o:p></o:p></pre>
<pre>====================================<o:p></o:p></pre>
<pre>Perpa Ticaret Merkezi B Blok Kat 13 Nr. 2568<o:p></o:p></pre>
<pre>TR-34384 Okmeydani Istanbul Turkey<o:p></o:p></pre>
<pre>Tel : +90 212 220 07 40 Fax : +90 212 210 47 01<o:p></o:p></pre>
<pre>e-mail : <a href="mailto:odilmac@bilko-automation.com">odilmac@bilko-automation.com</a><o:p></o:p></pre>
<pre>web site : <a href="http://www.bilko-automation.com">http://www.bilko-automation.com</a><o:p></o:p></pre>
<pre> <o:p></o:p></pre>
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