https://forge.codesys.com/forge/talk/Runtime/thread/c17cefeda1/2020-02-27T17:47:13.390000ZRecent posts to Ethercat FieldBus Lost Synchronicity2020-02-27T17:47:13.390000Z2020-02-27T17:47:13.390000Zeschwellingerhttps://forge.codesys.com/u/eschwellinger/https://forge.codesys.com58e0fa18fdfd1d8ce73e2a52f72d4558ce1fa6e3

<div class="markdown_content"><p>Hi,<br/> A rt_preempt patched Linux kernel is mandatory and 1:1 connected ethercat slaves...<br/> BR<br/> Edwin</p></div>

2020-02-27T17:47:12.356000Z2020-02-27T17:47:12.356000Zcookiyhttps://forge.codesys.com/u/cookiy/https://forge.codesys.com4c816914bdbb05ce115ba9311463ec7fe12696a3

<div class="markdown_content"><p>Dear sir:<br/> I have the same question with you. I also use a codesys with 2 hours and now when I set the sync to 4ms and offset 20%, it gets a error of fieldbus lost synchronicity when I try to control 5 real motor after about half ah hour. which is amzing is the drivers do not have any error about this,just error occured in codesys.<br/> I try to fiind the jitter of the ethercat task, about 1300+us, I think the jitter is too large so lead the error occuring,then I changed the offset with different values and find a best value is -20% with the jitter within 150us. And I think i get the real question about this error,but after about half an hour, i also got the same error and i find the jitter becomes more and more big.<br/> I really do not know the interal reason of the error "fieldbus lost synchronicity" and if it comes up with the task jitters.<br/> Do you got the answer of this ? <br/> Thanks for reading!</p></div>

2020-02-27T17:47:11.311000Z2020-02-27T17:47:11.311000ZAnonymoushttps://forge.codesys.com/u/*anonymous/https://forge.codesys.comf9e3f1152fd40100f4b27c57e80c14138637009a

<div class="markdown_content"><p><em>Originally created by:</em> scott_cunningham</p> <p>Great to hear. Sorry I forgot to mention the task priority!!!</p></div>

2020-02-27T17:47:08.377000Z2020-02-27T17:47:08.377000ZGiorgioThttps://forge.codesys.com/u/giorgiot/https://forge.codesys.comb0bb07dc08601114f497271816d79ac5e9663aa4

<div class="markdown_content"><p>Hi, <br/> I solved my own problem. I set ethercat task back to 4ms with 30% sync offset. Then i set the priority of the Visu task to 31 whilst the ethercat task priority was set to 0. Now the jitter is between +- 150 microsec and the lost sync error is gone.</p> <p>Thank you for pointing me to the right direction.</p></div>

2020-02-27T17:47:07.341000Z2020-02-27T17:47:07.341000ZGiorgioThttps://forge.codesys.com/u/giorgiot/https://forge.codesys.com9a9070d9026222f59a6875ae6926780ec7aa9b9a

<div class="markdown_content"><p>Hi, Thanks for you fast reply.</p> <p>Here are some results:</p> <p>with a Ethercat task of 4ms and 25% sync offset i get this: Max Cycle Time : 1830 microsec but an unreasonable <strong>Jitter Max: 6029 microsec e Min: -3531 microsec</strong> as you can see in the second picture.</p> <p>Then with an Ethercat task of 8ms and 50% sync offset i get: Max Cycle Time : 1732 microsec but an unreasonable <strong>Jitter Max: 6675 microsec e Min: -6685 microsec</strong> as you can see in the first picture.</p> <p>This Jitter values are likely to be the problem !!!! I've never seen Jitters so high. What can be the problem? I used 2 BBB with the same results.</p> <p>I use this kernel:</p> <blockquote> <p><strong>Zitat:</strong><br/> Linux beaglebone 4.4.14-bone-rt-r11 #1 PREEMPT RT Fri Jul 1 01:43:25 UTC 2016 armv7l GNU/Linux</p> </blockquote> <p>I tried with the OS installed on SD as well on the eMMC.</p> <p>EDIT: I also tried with a raspberry Pi 2 Model B</p> <p>Please help.</p> <p>Thank you</p> <p><img alt="IMG: Screenshot (62).png" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=2385"/></p> <p><img alt="IMG: Screenshot (59).png" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=2384"/></p></div>

2020-02-27T17:47:04.401000Z2020-02-27T17:47:04.401000ZAnonymoushttps://forge.codesys.com/u/*anonymous/https://forge.codesys.comfdc22be0ba0bb2eadb77876627a5c8d229ed487c

<div class="markdown_content"><p><em>Originally created by:</em> scott_cunningham</p> <p>Check your task execution time - average and max values. Your task cycle time could be too fast. I had a job where I used a 2ms Etherxat task time. Most of the time the task time executed in just under 2 ms. But occasionally it executes in 2.1 ms. Lost sync</p></div>

2020-02-27T17:47:03.363000Z2020-02-27T17:47:03.363000ZGiorgioThttps://forge.codesys.com/u/giorgiot/https://forge.codesys.com12303bb1498b01f5ccd62f00b3f96b9d9ae7bd57

<div class="markdown_content"><p>Hi,</p> <p>Thanks, that was just an oversight during some tests. In fact the error is still present despite the fact i removed the ethercat task from the visu task.</p> <p>What could be the problem ??</p> <p>Thanks.</p> <p><img alt="IMG: Screenshot (56).png" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=2383"/></p></div>

2020-02-27T17:47:00.434000Z2020-02-27T17:47:00.434000Zoptymalizacja2https://forge.codesys.com/u/optymalizacja2/https://forge.codesys.comfe175555fe50581f610ed266f4feb98fccaa8552

<div class="markdown_content"><p>The first thing that comes to my mind is to remove the etherCAT task from the visu task where it is duplicated...</p></div>

2020-02-27T17:46:59.366000Z2020-02-27T17:46:59.366000ZGiorgioThttps://forge.codesys.com/u/giorgiot/https://forge.codesys.com7ce35ad5a44799aa90a49d8760ad68169d0907f5

<div class="markdown_content"><p>Hi, <br/> I use a BBB with a RT kernel to control a servomotor through Ethercat.<br/> I use the SMC_FollowPosition block since new position values arrive in real-time each Ts milliseconds. (Ts can be 100ms or 1sec).<br/> I tried with MoveAbsolute and MoveRelative blocks as well with the same result.</p> <p>Unfortunately i always get this error and the motor stops spinning. <br/> I called the technical support of the driver's company and they told me to increase the sync offset up to 50% but i have the same error.</p> <p>How could i solve the problem?</p> <p>Thanks in advance.</p> <p><img alt="IMG: Screenshot (49).png" rel="nofollow" src="https://forum.codesys.com//download/file.php?id=2381"/></p></div>