How many EtherCAT servo motors can be controlled

[Purecade]

Hello，

I would like to know how many EtherCAT servo motors can be controlled by RevPi Connect via codesys? What determines this?
What about CANopen servo motors?

Thank you,
Cade

[j.magnano@kunbus.com]

Hello Cade,

servo motors will need a very fast clyclus time.
Our RevPi is limited to a max. of 5 ms, applications in EtherCAT below 5 ms will not be possible via our RevPi.

Thanks, Julian

[giuseppe]

Hello Cade,

@Cade: I took the liberty of summarizing your second question in your first post.

EtherCAT and CANopen use comparable concepts for drive control, but the bus physics are completely different.
With CANopen you are limited to 1 Mbit/s, of which about half is needed by the CAN overhead.
With CANopen you need 2 PDOs per drive (2 byte data, 6 byte data) for servo drive control and again a 6 byte PDO for status.
With EtherCAT you can pack several drives into one PDO, which is not possible with CANopen.
So it is hard to compare, except that EtherCAT is much faster. However, with EtherCAT there is the limitation of the Ethernet connection that is connected via USB2 in the RasPi 3 modules.
The limitations depend on the protocols, the application and the performance of the used hardware.

Here are some articles about performance:
https://kunbus-gmbh.atlassian.net/servi ... 1058439239 | Is there any information about the performance of the RevPi?

However, the performance is always dependent on the application and must always be tried individually, which limits it has.

Mit freundlichen Grüßen | Best regards
Giuseppe Pagano | Technical Support