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TMDSECATCNCD379D: Sync0 signal delay between slaves

Yiu Hang Li
Intellectual 460 points
Part Number: TMDSECATCNCD379D

Hi there,

We got another wired question would need some opinions on.

We got 3 custom servo motor slaves that's similar to TMDSECATCNCD379D on network. There is no problem connecting and running. However we found something when measuring their sync0 signal to check for how synchronized they are.

We found that 1st slave's sync0 signal is always ~7-8us ahead of other slaves's sync0 signal while other slaves's signal are quite in sync (less than 1us from what we can see). The ~7-8us delay is very stable, we can't see any drifting or jitter with respect to other slave's signal.

Did we missed something on slave's setting? Any setting will cause such delay?

Also another problem that may or may not related. Usually after a few hours running some slaves will report EtherCAT AL status code synchronization error. Will this caused by unstable sync0 signal?

  • 0
    TI__Mastermind 30255 points

    Hello

    I have not seen this. What EtherCAT master are you using? When you enable DC on the slaves, is slave 1 being set as the DC reference clock or not? Try that with enabled and disabled. Is there anything running slave 1 that could interfere with the ISRs?

    Best regards

    Chris

  • 0 in reply to Christopher Chiarella
    Expert 1670 points

    Dear Chris,

    we are a new developer of ethercat, so can you pls tell us where to check whether slave 1 being set as the DC reference clock?

    actually all 3 slaves are running the same code to run motor, which includes pwm isr and sync0 isr.

    Feng

  • 0 in reply to Christopher Chiarella
    Intellectual 460 points

    We are using a PCIe card called GEN card from Googoltech.

    Not that we know of. And we are not measuring ISR trigger but the hardware signal from ET1100.

    As Feng said is there anywhere to check is the slave being used as reference clock? I can't find any related flag on ET1100 register manual.

    Also another question, we found that consistently after running for few hours a slave's sync0 signal disappeared halfway. Do u know any possible cause that will stop sync0 mid way of communication?

  • 0 in reply to Yiu Hang Li
    TI__Mastermind 30255 points

    Hello

    In terms of the reference clock, I can detail where it is in TwinCAT. When you select the slave and go to the DC tab, there will be a checkbox regarding if that slave is the reference clock or not.

    I don't have any experience with the SYNC0 stopping. Did the EtherCAT master report any errors or feedback?

    I recommend asking the EtherCAT experts on http://www.ethercat.org/ forums

    Best regards

    Chris