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<p class="MsoNormal">Hello all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">i try to read some SDOs from a slave, the PDOs are limited and that values need not to be updated with high frequency.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">My first trial was using the function „ecrt_master_sdo_upload“ in a non realtime task.<o:p></o:p></p>
<p class="MsoNormal">Problem here besides of the blocking behaviour is, that it needs the slave position and not its alias,
<o:p></o:p></p>
<p class="MsoNormal">which i think is a problem in case of dynamically connected/disconnected slaves.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So i tried using the methods „ecrt_slave_config_create_sdo_request, ecrt_sdo_request_timeout ,ecrt_sdo_request_read, ecrt_sdo_request_state, ecrt_sdo_request_data“<o:p></o:p></p>
<p class="MsoNormal">in the realtime task.<o:p></o:p></p>
<p class="MsoNormal">That works, but with this i see a process „EtherCAT-OP“ in the task list with a cpu load of more than 20%, while my test application consumes about 1%.<o:p></o:p></p>
<p class="MsoNormal">This is for reading only one SDO. Without reading the SDO „EtherCAT-OP“ is also at about 1% load.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So my question, does reading one SDO really cause this high cpu load? Is there something wrong? Or am i on a totally wrong way to read some SDOs?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">My test application is mainly derived from the „user“ example, of course i can share the source if of interest.<o:p></o:p></p>
<p class="MsoNormal">It uses a cycle time of 5ms, so it should be not too fast.<o:p></o:p></p>
<p class="MsoNormal">It runs on a plc (Cortex A8) with Preempt_rt patch, etherCAT version is 1.6.1.<o:p></o:p></p>
<p class="MsoNormal">There are 4 slaves connected, 3 Beckhoff and one NORD inverter, from which I need to read the SDOs.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I really appreciate receiving some tips!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best regards<o:p></o:p></p>
<p class="MsoNormal">Franz<o:p></o:p></p>
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