Every stepper that I have ever used is 200 steps or 1,8 degree. It is kind of baked into their very bones.
It certainly is not going to be 230 steps per rev. It just isnāt.
Gecko have to my knowledge been doing ten micro step drives since forever. Maybe their most modern drives may have gone the Chinese route. But these are definately 10 micro steps. These G201s I have been using for years. Rock solid.
As for gear or belt/pulley ratios it is basic physics. 14 tooth to 120 tooth. Hard to get it wrong.
If say, I made a miscount, and there were 15 teeth on the smaller pulley then the anomaly woud be considerably larger.
However I have made math mistakes before. If that is the case I would be happy to have the error highlighted.
I do appreciate your taking the time to look at this.
I am using the test feature in the āRotary Setupā and also confirming this with a 360 degree move.
Setting circumference at 360mm and jogging a distance of 360mm.
I can only see three possibilities.
I made a mistake in the math. This was my first question.
The stepper driver is not delivering ten micro steps. Highly unlikely as the same drive runs the Y axis when not in rotary mode and Y axis moves correct distance as per toothed belt calculations.
The controller is not putting out the stated number of steps.
I could attempt to measure the step number with an oscilloscope. Not sure I can do that but might give it a try.
Yes I think if I can manage to actually count the steps output that would narrow it down.
Just not certain with the equipment and skill available that I can achieve that.
I will make an attempt today.
If you can run the two tests I suggested that would be easier. No fancy equipment needed.
First test the gears:
Place something on the gears that points in a single direction while allowing you to rotate the gears.
Turn small gear one full rotation
Measure angle of larger gear. You could print an angle chart if you donāt have anything else that could be used. The longer the āpointerā the more exaggerated any measuring error.
Next test stepper motor:
With the pointer still attached, command what you think is 1 full rotation.
Measure and confirm rotation
If the error is only seen in one of the two tests then that eliminates the other side from the problem. If theyāre in both side then youāll need to account for that separately but should allow you to further narrow in.
AS accurately as I can measure one motor rotation turns the bigger pulley exactly 42 degrees As expected.
These toothed belts do not slip or exhibit any measurable backlash at these very light loads.
Even swapped out the stepper driver to see if that made a difference. No joy.
I failed in my attempt to count the pulses with an oscilloscope. Probably just my lack of expertise.
At the setting of 17270 it achieves exactly 360 degrees. At the calculated 17142.86 it falls 3 degrees short.
When all is said and done, it really does not matter in any practical sense. The rotary axis does exactly what it needs to perform the task⦠It was just my curiosity as to why the anomaly existed.
So I am going to leave it here. Thankyou very much for your input.
What are your motor drivers set? 2000 steps/rotation?
@berainlb best idea is to view the actual motor shaft⦠Iām also in agreement, donāt see anything wrong with the old retired carpenter math that I can seeā¦lol
Are these NEMA types ⦠Iām not familiar with theseā¦
This is how I set them up on my Ruida, maybe that will help⦠although I think much of a variance would make a ālargeā difference⦠So your procedure was probably very similar.
I started building CNC machines about 18 years ago and Gecko were not new then.
They were the go to supplier for non industrial builders before all these Chinese drives started being available.
A long standing USA manufacturer.
As explained above I am abandoning this curiosity pursuit.
Laser is performing great and doing all I ask.
The fact that there is something unknown going on, bugs me but I will get over it.
Geckodrive controllers seem more complex than my stepper driver.
Which model is yours ?
could you try the binary divider instead of decimal, maybe *16 or *32
I have one motor on *32 and one on *16 which makes my motors much smoother.
A notchy motor can miss pulses.
The drive in question is the predecessor of to this one.
These drives do not have selectable micro step counts. Hard wired ten micro steps.
They believe ten is optimum and more is just diminishing returns.
I have never built or operated a stepper driven machine that has lost steps.
It is one of those often believed myths that only belong to poorly designed and setup machines.