Sanitycheck my plan: ethercat + stepperonline A6

Hello folks, this is my first post!

I've currently got a mach 3 based 3 axis CNC, and i'm building another one (which for these purposes can be thought of as a printNC in terms of design, dual drive for the main axis, single for the rest) for which I plan was reuse the control box, based on open loop steppers, to get it going and then migrate to linuxCNC. I still got some months ahead of me on that build and time to change my mind and do something about the controller sooner. I've no experience configuring linuxCNC but i'm a developer doing stuff i've never done is basically what we do.

I'd like to go all the way to the other end of the spectrum with ethercat servos. Thesem plus a small ethercat IO module would allow me to skip mesa cards. Given that premise, what do you guys think of these servos? (Try to ignore the fact that i'd have to pay more in shipping and taxes for them than the hardware is worth. That is just the reality for me living in AR and would apply to all alternatives similarly)
https://media.discordapp.net/attachments/1332732662107869308/1494434027028091041/Screenshot_2026-04-16_at_5.24.53_PM.png?ex=69e297a5&is=69e14625&hm=fc0960a66f042b806facd98201b57cecbe5abb092fd39c1c1cd010140933690c&=&format=webp&quality=lossless
Now, i KNOW i'm not buying leadshine or get 1 click tuning. I'm not asking if it'll be easy to get it going, I know it won't be trivial. I want to know if there's enough to read that i could get them working, and when i do, will i be happy with how they perform. Now, I've looked around and there are definitely people using these servos, asking questions, and other people responding to them, but they never seem to post some nice shiny video of they machine working in the end which is what worries me.

if there's anything regarding my build that'll affect the response let me know and i'll add it. Thanks a bunch!
 

Sorry, pasted the image, and it looked good, but apparently it ended up referencing a discord image. Here it is.

Yes, same as those. I had seen the success case from dschultz in there around the middle of the thread, which is encouraging, but I'm mostly polling on thoughts from people that might have succeeded with them and not ended up coming back to post about. Also, in general about anything that I might not be considering about my linuxCNC + ethercat in one go.

I don't think you will have any problems getting the drive going. I'ver noted many attempts with this drive have been flawed from the very beginning. The fact is they are cia402  drives and this means the core Ethercat registers are standardized and there are components to follow the cia402 state machine to start the drive. 

I would use Linuxcnc homing and forget about internal homing for now because of your 2 joint main axis (We would say XYYZ). Internal homing of a joint axis by Ethercat is a bit unknown/unsupported. Note having homing switches on both sides is mandatory on gantry machines. The gantry is auto squared on homing.

There should be some inputs on the servos themselves you could use if configured to be generic inputs in your ethercat-conf.xml. The safest/easiest IO would be to use Beckhoff EK1100 but there are several on AliExpress like Rtelligent, deiwu (I have used both, configs here github.com/rodw-au/linuxcnc-cia402) and another with an encoder input called catio-a which is mostly documented here on the forum. I have one of these and the forum config generally works (I have one of these too).

Note that the Beckhoff encoder modules are quite expensive but with a printnc style spindle, you probably don't have a spindle encoder. You could use RS485 modbus for spindle control with a USB or RS232(preferred) RS485 interface. This works pretty well with ethercat. I've been playing with the modbus control on the catio-a and  read one register once but then could never repeat it after adding all of the required registers.

Good luck

That info is pure gold rodw, thanks a bunch!
- Dual homing switches were the plan yeah, just checking if it's fine to have a single limit switch or if i need one i both sides?
- I'm currently using a PWM output + an RC circuit to get 0-5v for my spindle RPM but had already got the suggestion of using serial to talk with the VFD, glad to confirm that is a good approach.
- IO modules, if i can get what i need from used beckoff listings on ebay i might go that way. The servo inputs should take care of all the homing/limits, and if the VFD is handled separately, one of the most common ones with 16 IO might just do for e-stops, probes.. And i can always just add another module if that changes.

The concept of the break is also new to me, is this something you need to config or it's something that's handled automatically between the servo and its driver?