1F sets the X and Y motor resolution to 400 SPR, in order to have the Masso MPG work in smaller increments, Peter with Masso recommends setting the motors to 800 SPR.
Any idea why 1F sets them so coarse? Any down sides to increasing the resolution to 800?
Pat
I read about the same info and changed all my axis to 800 about 2 weeks ago, and so far, no issues. It did stop some of the low level “growling” of circular movements, but didn’t completely eliminate any sounds. I would consider it safe. I reloaded by machine settings to re-do the tools lists on F5, and forgot that the original files would re-write back to 400, and the only way I figured it out was 48 inches on screen was really 24 inches when it stopped the X or Y, so after a forehead slap, I set them back to 800, and downloaded my new machine settings to my Masso config file so I won’t do that again.
F5 is the conversational screen, did you mean F4?
I didn’t think I would have to do anything but change the resolution from 400 to 800, I would not think this change would affect previously posted programs.
Pat
Hi Pat,
Yep, my bad, F4 is correct. On the Elite, you have to make 2 changes, One is the F4 screen change for each axis from 400 resolution to 800 resolution and you also have to change the corresponding dip switch on each motor. The dip settings come from Onefinity with all of them pushed toward the motor shaft end, changing dip #1 toward the end plate of the motor changes it to 800 resolution as well and that is the necessary changes needed.
One is the F4 screen change for each axis from 400 resolution to 800 resolution…
I was looking for the PPR setting in the F4 screen but according to the documentation it is in the F1 screen. https://docs.masso.com.au/wiring-and-setup/setup-and-calibration/axis-calibration
Rob,
That was probably me that got folks confused about where to find the resolution settings, they are not on the F4 page at all. The real solution is found on the F1 page, and you must double tap each axis individually to bring up the sub-menu that has the Pulses per Revolution (PPR) and set them from 400 to 800. Do also remember that dip switch #1 on each Masso motor has to be placed toward the motor end plate (not the on position) for this change to work, as well. It is a 2 step procedure.
Interesting threat. I heard that setting the resolution higher solves issues with motor interference (growling noise when x and x axis move at the same time). It seems the whole machine is vibrating at certain resonance frequencies.
My question is, how high is too high? What are the drawbacks of setting the resolution to say 6200 or even 40000?
I am looking for precision, not speed, I image setting the resolution higher would make the 1F more precise up to a certain limit?
There was some discussion here of losing torque when changing the step count. It would seem to me that going from 400 to 800 would increase the torque of the system because you are going more counts to get the same distance.
It is actually the opposite.
I shared the below comment in another related thread…
From the research I had done when building my set-up I found that when increasing the number of micro-steps per full step, the incremental torque per step drops off dramatically.
Whether this results in a noticeable change in performance with an Elite CNC - between a Masso motors 400 vs 800 setting - would depend on many factors.
I do not know of anyone who has done any quantitative testing of this.
Its funny, if you look at torque verses speed charts, what step resolution would they be using to develop the chart?
Pat
Pat, that is an excellent question!
Here the charts from the Masso website for the 2NM motor, remember that the Elite motor is 1.2 NM.
I am still wondering if augmenting the pulses per revolution would increase the precision of the 1F even with the risk of losing power. And also how much power would be lost.
Why did 1F think that 400 pulses per revolution is ideal for the CNC? Were they just looking for speed?
I had found this interesting, and it highlights a difference in the torque measure impacted by micro-stepping.
At 400 pulses per revolution and a 16mm thread pitch each step is .04mm or .0016 in, that should be sufficient for wood working projects. Increasing to 800 PPR would effectively double the theoretical precision to 0.2 mm or .0008 in.
This article also discusses resolution - Accuracy and Resolution - Gecko Drive
It explains that most steppers given their structure will have a +/- 5% non-cumulative error with respect to the location of a step, and given this, micro-stepping beyond 10 yields no real added resolution (there are noted exceptions).
Ok I am starting to understand now
At 400 pulses per revolution and a 16mm thread pitch each step is .04mm or .0016 in
I just made a spreadsheet which shows the theoretical max precision with a certain PPR setting:
It makes total sense now that there is no reason to go beyond 2000 pulses per revolution.
Of course considering that microsteps are not always linear and in addition to the errors TMToronto mentioned, those numbers should be read with a pinch of salt. I am now thinking of setting my pulse per revolution to 1600 or even 2000. That should give me very clean surfaces and smooth curves, I sometimes do carve tiny objects.
I do vaguely remember that the Buildbotics controller has a soft max precision of 0.05mm.
Just as a comparison, a higher end CNC machine like the Roland MDX-50 has a mechanical precision of 0.01mm. I doubt that the Onefinity can reach that, but it might get close.
It is also good to know a higher PPR (pulse per revolution) should not affect the torque at all.
On a side note, I just lowered my max acceleration from 500000mm/s2 to 100000, I think that is a better setting for me. The QCW table shakes less now. Of course it will slow down my carves. I might reduce that number even further, until the CNC becomes too slow…
Thanks everyone! Sometimes this forum is very productive!
Here a stament from Masso, I am sure they won’t mind if I post it here:
The Pulses Per Revolution (PPR) setting defines how many pulses the drive will take to turn the motor shaft one complete revolution. This setting can affect the speed, torque, and precision of your motor.
In terms of speed, a higher PPR can result in a slower rotation speed because the motor needs to process more pulses for each revolution.
For torque, it’s more related to the motor and drive design rather than the PPR. However, using a higher PPR can sometimes reduce torque at higher speeds.
Regarding precision, a higher PPR can potentially increase precision because it breaks down the motor’s movement into smaller steps. However, there’s no advantage to using huge step rates with large gear ratios. Breaking one rotation into a million steps will not help accuracy and give you a rotary axis that is slow. A value of 8000 to 10000 Pulses per revolution should be more than enough for most applications.
Remember, these are general guidelines and the actual impact can vary based on your specific motor and drive setup. Always refer to your motor drives documentation on how to setup PPR.
​
The original thought for this was some folks using the Masso MPG wanted a finer resolution and Peter recommended setting the PPR to 800.
Just for some frame of reference, mine is accurate enough for what I do, I work only with wood and well wood does compress when machining and also moves all the time anyway, especially the wrong way.
I found it interesting that it was felt that the finer resolution led to a quieter machine, I would like to know more about this but my machine seems pretty quiet anyway.
Pat
For those that enjoy continued reading, here is one of several articles I had bookmarked on the topic when I was looking to learn more about stepper motors:
Brilliant Explanation, that makes so much sense now!
I just switched to PPR of 2000 and cut some air, I did not encounter any problems.
First I opened the motor cover an set switch 1 and 4 to the off position, with the controller powered off. The I change the X,Y and Z axis motor settings in tab F1 and saved.
I also changed some other settings, and the wild noisy janky beast became much tamer.
I know this might not be for everyone, but as I said, I am not looking for speed but precision.
The top line of the picture it actually shows the Axis resolution, perfectly in line with my PPR/step size chart from post 15.
I reduced my Acceleration further from originally 500000 mm/s2 to 25000 mm/s2. It has still plenty of jerk, maybe still too much for me. The 6m/min speed limit is temporary, I think I want it back to 10m/min for roughing and limit the speed for the finishing tool path in Vcarve.
*What I just notice is that it looks like at a max pulse rate of 12.5 kHz the motor would max out at 100mm/sec, which is 6m/min if I did not make a mistake.
I have to think about that, a PPR of 1000 would have a max speed of 12m/min, which means it would not limit the max speed of the 1F of 10m/min… I hope my math is correct, it is past midnight.
I am making a bold claim now:
The Onefinity Elite setting for the PPR (pulse per revolution) should ideally be set to 1000, not 400. This would give the Elite the highest possible precision without compromising the max speed.
Prove me wrong.
I’ve been following various posts on resolution of the motors and it’s impact on making the elite series run more smoothly (for some who have experienced rough running motors). I put in a ticket to Masso asking what impact the change from 400 to 800 has on torque and Peter was quick response back with “Pulses per revolution do not affect torque, just resolution. Speed affects torque.”
