High jitter between eCAT Master and eCAT Slave

Tharangini Chinnadurai

Other Parts Discussed in Thread: TMDSIDK437X, TMDSICE3359

Hi,

I am using TI ethercat master (TMDSICE3359 ) and TI ethercat slave (TMDSIDK437x). When I run the demo program, "EC-Master-V2.9.0.06-SYSBIOS_AM335x-Protected" with TI slave, with cycle time = 500usec, the level of jitter is high. I expected jitter to be as low as 1usec. But in (pls refer the attached wireshark image) reality, it is more than 10usec. Is there a way to reduce this jitter?

Thanks.

over 9 years ago

0 Tharangini Chinnadurai over 9 years ago

Intellectual 280 points

I made these changes while capturing the wireshark image:
I changed 2000 to 500 in EC-Engineer while generating eni.xml file, used this to create MasterEni.c. In the master demo, changed demo_parameters from 2000 to 500.

0 Biser Gatchev-XID over 9 years ago in reply to Tharangini Chinnadurai

TI__Guru**** 393215 points

The EtherCAT experts have been notified. They will respond here.

0 Paula Carrillo over 9 years ago in reply to Tharangini Chinnadurai

TI__Mastermind 40580 points

Hi Tharangini, 10us of jitter sounds correct. FYI, EC-Master prints Cycle Time (avg/max) which could be used as well for getting an idea of the Jitter.

In order to reduce jitter, have you explore to use DC?

Another option could be to use PRU-ICSS EMAC Time Triggered Send TTS, however, we currently don't have ready PRU-ICSS EtherCAT master + TTS for AM335x. FYI, We have a TI design which demos EtherCAT master +TTS for AM57x platform, please see section 10 of mentioned TI design document for additional information.

Thank you,

Paula

0 Tharangini Chinnadurai over 9 years ago in reply to Paula Carrillo

Intellectual 280 points

Hi Paula, Thanks for the reply. Yes I too don't think DC is enabled.

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High jitter between eCAT Master and eCAT Slave