Yeah I figured you knew how stepping worked, but I’m in a mansplaining mood so forgive me.
64 dose seem odd, but also too perfect (being a power of 2) to be a coincidence. But I can’t come up with why it would be different either. Maybe someone can drop some knowledge on us 
I would guess the steps is relative to the encoder, not the poles of the motor, to keep the servo firmware simpler. And then they have a mapping (established during calibration) to convert the encoder positions to the phase of the current through the windings.
I’m confused why lower microstepping would have better torque, since it only affects the format of the commands, and the active side driving the motor should be equivalent.
I am wanting to try these out one day and see if they are much more power efficient (they should be) when operating with low loads.
Oh yes they seem to be much more power efficient. My old motors were much bigger than these ones, yet they were heating pretty fast. So far these one remained totally cold during my tests.
That’s awesome.
I never really thought of that. It pretty much does what the TMC drivers call cool step. That could really make these worth the money. You can turn the max current up because these will only use it when it is really needed keeping things cool and safe. Heck and you can probably use smaller lighter steppers because of that.
Dang Dui, you really have me wanting to mess with some of these.
Please give me an excuse to throw cool techy looking motors like this on my machine
Lol, well so far I don’t have the good news I was hoping for.
First attempt was a complete disaster, the print head was wobbling like crazy, I had insane layer shifts, the two motors on each axis were not even in synch.
I didn’t take pictures as it was just looking like a complete random mess.
On second attempt, I lowered accelerations and speeds. It very slightly improved, at least I was able to see a shape vaguely resembling something. But still total garbage.
As you can see, the thing just wobbles teribly and sometimes get stuck.
So at that point I was really disappointed and I started thinking that those things were garbage or at least not at all compatible with my particular setup. Very frustrating.
But I kept digging and as it turns out the main root cause might be the communication speed between the duet board and the motor drivers. The Duet is configured for working with the TMC drivers, whic havee a very fast communication rate.
The drivers on the servo are much slower, so they need a slower step pulse.
So I tried to lower the pulse timings in the firmware, and this time I did got something actually resembling a print. Sorry I forgot to take pictures since it was already very late and I was exausted, but at least this time the layers were well aligned on top of each other, the motors were in sync and globally it was resembling something.
But I still have a lot of stuttering so there are some very visible wobble on the outside surface, like big waves. I think this is a PID issue because the steppers try to reach the destination and they overshoot because of the very high mass of my print head (lots of inertia). Unfortunately, I’m not clear on how I can edit the PID settings on these particular servos since I haven’t seen anything of the sort in the menus. And as usual, there was no documentation provided with the steppers so I guess I’m on my own.
So, all in all, so far I can’t say if those will work or not. If I can adjust the PID and remove this stuttering that creates waves, then it will be ok, but otherwise it’ll be unusable. So let’s wait a little and see. At least I got them to work, even though it’s very poorly.
Bummer, kinda like the TMC’s and sensorless homing. All that new fancy stuff is complicated and harder to set up than advertised, sometimes it doesn’t always work as promised. In this case I am wondering if something obvious was missed in setup or settings or just some bug fixes need to happen.
Do you know if ‘calibration’ establishes only steps per mm or if it also records some form of momentum or friction that is used for PID settings? Maybe it is tuned with no weight and the large weight of the gantry makes it very different from optimal coefficients.
No Idea.
All I know so far is that you can edit the PID using a complicated process of connecting through a dongle on serial port but you cannot do that with the screen menus, which I found utterly stupid since PID tuning usually is a guess work that takes a lot of trial and error, that’s exactly the kind of things for which the screen would be perfect for.
The other things you can tune using the screen are microstepping or direction, which are stuff you never touch once it’s set up anyay, so I really don’t get what the people who designed these menus were thinking.
I’m trying to find information but apparently few people use these so it’s very hard to find anything interesting.
That’s quite frustrating.
With open loop steppers, there is no logic involved. They don’t ever have to decide if they are in the right place or not. They just step exactly where they are told, until they reach their limit.
With the open loop, it is constantly asking, “is this the right place?” And they are using the sensor feedback to decide. It is more complicated, but I don’t think that is the root issue. It think it is just much harder, and dependent on the quality of the sensor, susceptible to interference, and depends on good software settings.
It may be something simple. I was hoping changing the speed of the interface would help. Or maybe the steps/mm would? It may also be that it just needs some different PID settings. If it is just wiggling while sitting still, then that has nothing to do with the weight of your gantry.
It may also be that it needs some serious firmware updating. That is the nature of the beast.
Well so far it turns out to be a f***king nightmare. It’s insanely complicated to edit this firmware, I’ve spent 2 days on it already and couldn’t get anything working.
I had every possible problem at every possible step.
Had to install visual studio code, and then some add on called platformio which took me more than a day to get barely working with some functions missing,
Had to get myself a Jtag flasher
Had to make some kind of wiring, which didn’t work at first because those morons at bigtreetech made a very confusing wiring sketch.
Had to guess that the product needed to be powered on to be able to flash it, which was written nowhere in the extremely poor documentation
Was finally able to flash the default binary version of the firmware provided by the manufaturer, so at this point I thought it would be ok
Edited the firmware using the source bigtreetech provided on github, using the method they recommend,
Compiled it with no error
Flashed it
Not good, the motor refuses to calibrate and does weird stuff.
Naturally, at that point I thoughtI was the moron, so started back again with the original sources, this time not changing anyting to them and compiling directly.
Flashing. Same exact behavior.
Flashed the original bin file. Back to normal.
So apparently the sources they provide have an issue, which renders them useless after compilation. Great, thanks Bigtreetech, I spent two days for nothing, awesome.
Anyway, it’s horrific to work with, I think I’ll just throw these away, it really starts to piss me off now.
I cannot recommend this product, it’s not user friendly at all. I don’t understand why they don’t bother to add the PID setting in the menu, I saw many users asking for it and they don’t seem to care.
They also seem to say that the PID can be edited in an awful software they made by directly writing hexadecimal (very user friendly, kudos).
Here’s the manual btw:
In order to do that, they say that I “just have to connect the motor to my computer”.
Great, but how???
I have absolutely no idea how I’m supposed to physically connect it, there’s no usb port and when I try it with the JTAG it doesn’t see it as a COM port.
I do see some Rx and Tx labelled ports on the board, so I guess I might have to use these, but how?
I hate chinese companie’s manuals, whoever wrote those useless things deverves a long and painful death.
Any help is very welcome, at this point I’m really stuck.
Probably using a uart usb dongle. A common name is usb ftdi.
But more generally. That sucks. The skills you learned are pretty useful (vscode/pio are strong, flashing over jtag can save some boards). But having an open source product ship with a magic binary is BS. Editing critical parameters through jtag is a joke.
Well as it turn out their binary file is far from magic. I reinstalled the motors in the printer after flashing them with the bin file they have in their repository, calibrated the motors a usual, and then none of them turns anymore when I ask them in the printer interface.
Everything they shared on the repository is garbage and now my motors are bricked until I find a valid version of the firmware. Great job Bigtreetech.
Brutal.
Well I gave up and re installed my trusty old steppers. I made some slight modifications so I can drop the servo backs later, menawhile I’ll try to send them back to the manufacturer to at least get them flashed back to a working condition, or maybe better, gt them swapped for the v1.0 which works exactly the same but at least does have some support by the community.
So at least my printer now works fine again, but still open loop.
That’s a bummer man! 
I hope you it works out in your favor in the end.
I have 2 of these on my Geeetech A10M and they are working great, but they don’t have to synch with two in each axis.
I hear there is supposed to be a V2 coming soon that has a better PC interface. I agree that the OLED interface leaves plenty to be desired.
On the plus side, when testing I grabbed the bed to make it skip, as soon as I let go it snapped right back to position. A10 layer shifts are a thing of the past.
@vicious1 if you want to play with them I’d donate a couple of the conversion kits to you… Let me know.
Thanks, but if there is a V2 coming I better wait. I am really interested to see if the current limiting would do it’s thing, more so than the closed loop. I think I can get what I want out of the TMC’s (coolstep?) without adding cost. Or at least test it since I do believe it is enabled on the SKR pro.
