How good is Ethercat motion control?

ihavenofish wrote:

--snip--
I don't know if that's a linuxcnc thing, and ethercat thing, or just a stupid omron thing.

Other than these quirks though, its great and I would not switch back for anything haha.

What model number Omron drive is this? Also, are you using some form of CIA402 component with it? Which one?

I have had a keen interest in Omron servos for a while, but never actually worked with one of those. One of my upcoming projects could use one, now knowing there is "some mysterious bug" of sorts really catches my interest. If I manage to carve out some time for this, I would like to acquire the hardware and investigate the problem.

@NWE

Industrial drives like Omron should not show behavior that depends on history or on how many times you repeat a homing cycle. They don’t “degrade” or become inconsistent just because you run the same sequence again and again. If behavior changes depending on history or number of cycles, that’s almost always a bug in the integration logic (state not reset, counters not reinitialized, missing edge detection, incomplete state machine), not in the drive or in EtherCAT(fieldbus) itself

how many CiA402 implementations are we talking about?
which one are you actually using in your setups? For example, are you using the stock cia402.comp, a modified version, or something else on top of LCEC? And with which drives / modes?

I know this thread is about EtherCAT motion control in general, so to avoid derailing it, maybe it makes sense to open a separate thread focused on this specific Omron / CiA402 / startup behavior case, where we can look at the actual component, configuration and state machine logic in detail

NWE wrote:

ihavenofish wrote:

--snip--
I don't know if that's a linuxcnc thing, and ethercat thing, or just a stupid omron thing.

Other than these quirks though, its great and I would not switch back for anything haha.
What model number Omron drive is this? Also, are you using some form of CIA402 component with it? Which one?

I have had a keen interest in Omron servos for a while, but never actually worked with one of those. One of my upcoming projects could use one, now knowing there is "some mysterious bug" of sorts really catches my interest. If I manage to carve out some time for this, I would like to acquire the hardware and investigate the problem.
 

I don't think any of my issues are anything to do with the omron drives. I know 100% the first one is explicitly a conflict between ethercat and modbus naming and start up synchronisation. it is basically reinitialising the drive over and over and over The question is.. WHY?

The new one about joint errors/limits just showed up at random and went away. I think it was related to some stored values that got cleared on reboot, but not simply on linuxcnc restart. Like is was storing the wrong home or last encoder position etc. (i had shut down linuxcnc and rebooted the drives, then restarted linuxcnc). Probably an edge case that likely will never show up again.

The ffirst one is more important, cause every 10 times or so it starts it wigs out.
 

Marcos DC wrote:

@NWE


I know this thread is about EtherCAT motion control in general, so to avoid derailing it, maybe it makes sense to open a separate thread focused on this specific Omron / CiA402 / startup behavior case, where we can look at the actual component, configuration and state machine logic in detail

 

I have multiple threads on these things, with files posted
The point of commenting here was to say that ethercat in linuxcnc can be a little flakey here and there, but still the way forward.

@Marcos DC
I assume my best chance of diagnosing the behavior is to start with identical hardware and configuration.

I do not know enough details about ihavenofish's issues to point at any specific bit at the moment. I suspect some unexpected interaction between the Omron drives and the LinuxCNC CIA402 component but that is just conjecture at this point. I would like to take a closer look at CIA402 component behavior while running real hardware on my workbench.

ihavenofish wrote:

I have multiple threads on these things, with files posted
 

Thanks, I will search...