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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,<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">First off, my understanding of setting up the DC system is that each slave that wants a Distributed Clock setup calls ecrt_slave_config_dc()
specifying the sync0_cycle time and the sync0_shift time (and sync1). The sync0_shift time should be specified as the offset from the nominal start of cycle time, which is specified by the very fist call to ecrt_master_application_time().<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">Therefore your cycles should always start at: initial_master_application_time + cycle_count * cycle_time<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">Where you start counting cycles as soon as the first ecrt_master_application_time() call is made.<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">I set my sync0_cycle to 1000000 (1ms) and sync0_shift to 500000 (0.5ms). After waking up at the beginning of the cycle I then have 0.5ms
to send my EtherCAT frames and have them be processed by all slaves.<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"><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">As to answering "</span></font><span lang="EN-US">To solve the problem i have to know the systemtime, the next sync0-signal is generated
in the slave. Does anybody know if this time is available in a slave with dc-support ?</span><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"><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">If the slave has a 64bit DC you should be able to calculate the next sync time as "initial_master_application_time + cycle_count * cycle_time
+ sync_shift".<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">If the slave has a 32bit DC its more annoying reading the clock but it should be the same calculation, but then remove the top 4 bytes.
(You get 4.2 odd seconds before the clock rolls over.)<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"><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">Looking at the ET1100 datasheet document there is a register 0x0990:0x0997 which says it is the "SYNC0 Start Time" - Local copy of System
Time (T_localtime + T_offset) (From Section 9.1.5).<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"><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"><st1:PersonName w:st="on"><font size="2" color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial;color:navy">Graeme Foot</span></font></st1:PersonName><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"><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"><o:p> </o:p></span></font></p>
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<p class="MsoNormal"><b><font size="2" face="Tahoma"><span lang="EN-US" style="font-size:10.0pt;font-family:Tahoma;font-weight:bold">From:</span></font></b><font size="2" face="Tahoma"><span lang="EN-US" style="font-size:10.0pt;font-family:Tahoma"> etherlab-users-bounces@etherlab.org
[mailto:etherlab-users-bounces@etherlab.org] <b><span style="font-weight:bold">On Behalf Of
</span></b>WIEGAND Ralf<br>
<b><span style="font-weight:bold">Sent:</span></b> Wednesday, 2 April 2014 05:23<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> [etherlab-users] DC-Synchronization - Sync signal generation</span></font><font size="3" face="Times New Roman"><span lang="EN-US" style="font-size:12.0pt;font-family:
"Times New Roman""><o:p></o:p></span></font></p>
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<p class="MsoNormal"><font size="2" face="Calibri"><span style="font-size:11.0pt"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt">Hello,<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt">first of all, thanks to all etherlab-developers for their great job.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt">I have a question about the activation of the sync-signal generation with distributed clocks. I use the ethercatmaster 1.5.1 with the dc-patches from
<st1:PersonName w:st="on">Graeme Foot</st1:PersonName>, kernel 2.6.32.11 with rtai 3.8.1. The application is running over the rtdm-interface and the masterclock is synchronized to the reference clock in slave 1. The slaves are particular developed for us from
external companies (FPGA-based designs with Beckhoff IP-Core). The synchronization of the masterclock with the reference clock, like the patches from
<st1:PersonName w:st="on">Graeme Foot</st1:PersonName>, works very well. But i see a constant phase offset between the sync0-signal and the incoming frame (SOF). With every restart of the application the offset is constant during runtime, but with another value.
If the value is in a special range, i read the same input pdo values between two cycle times from the slave. To solve the problem i have to know the systemtime, the next sync0-signal is generated in the slave. Does anybody know if this time is available in
a slave with dc-support ?<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt">Thank you in advance,<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span lang="EN-US" style="font-size:
11.0pt">Ralf Wiegand <o:p></o:p></span></font></p>
<p style="margin-bottom:12.0pt"><strong><b><font size="2" color="gray" face="Arial"><span lang="DE" style="font-size:10.0pt;font-family:Arial;color:gray">Ralf Wiegand</span></font></b></strong><font size="2" color="gray" face="Arial"><span lang="DE" style="font-size:10.0pt;font-family:
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