Increase travel feed speed in OpenPnP. Travel feed speed from Duet web control is way faster.

[Fern528]

Hello everyone, 

I noticed that the speed while OpenPnP controls my duet controller is less than the speed if I run the machine via the web control at max feed. I assume it has to do with the driver settings for the motion planner. As of now I switched to EuclideanAxisLimits with max speed set to 0 per the  GcodeAsyncDriver · openpnp/openpnp Wiki · GitHub this still runs slow. I also set my jerk in the axis settings to a ridiculous high number and that initially helped the speed dramatically from the snail motion it was doing initially. Those are the two settings I have changed to improve the speed. currently thinking about upgrading the motors to push the duet max feed even higher and if openpnp is less then maybe then it will run at a decent speed. 

Question: does the backlash comp. affect the feed rates? 

If anyone has worked with duet boards and OpenPNP any advice is appreciated. 

Thanks, Fernando 

[Fern528]

I just ran a sanity check had the web control and openpnp opened side by side and noticed. jogging by 100 mm using openpnp the max feed rate is reached! During a job is when the speed seems to be lower. also, my max feed rate seems low only 600-800mm/s due to current motor and driver setup. 

Could it be during the job the travel distances are much shorter so top speed will never be reached? Could I increase the acceleration settings in the duet config to improve speed on short travels? Just noting thoughts and actions to try tomorrow. 

I will definitely look into upgrading my XY motor setup to increase that 600-800 mm/s limit. 

running generic dc servos for the XY with the duet3 6xd and the z,u,v and a,b,c rotation motors are on a duet3 6hc. Thinking about upgrading to clear path servos for the XY for more speed. 

[Jan]

Hi Fern528!
The key for speed (CPH) is acceleration. Feed rate is rather
insignificant as it is seldom reached.
Backlash does not affect the travel speed/acceleration. It's used to
compensate for mechanical imperfections by eg. stopping a little earlier
or going a small step backwards.
Jerk only effects motion for ModeratedConstantAccleration and above
(simulated 3d order or true 3d order). If set to 0 it has no effect.
With ModeratedConstantAccleration (the recommended setting) Jerk is used
to limit acceleration if motion continues in the other direction. This
reduces mechanical ringing and causes speed reduction. As acceleration
is then a function of jerk, do not (or at least carefully) try to
increase acceleration as it might - under other circumstances - result
in overloading the motor (loosing steps, inaccurate motion).
I'd recommend to use ModreatedConstantAccleration and start with jerk =
0. Then play with the acceleration settings (on short moves to limit the
effect of feed rate) until the machine does not follow. Then you can
play with the feed rate setting on long/very long moves (to make them
dominated by feed rate). Finally you can reduce mechanical stress using
jerk. The effect is best visible by setting up a back and forth test
motion. (remember, that reasonable jerk settings are about one order of
magnitude larger then acceleration.)

Jan

On 23.10.2025 02:53, Fern528 wrote:
> I just ran a sanity check had the web control and openpnp opened side by
> side and noticed. jogging by 100 mm using openpnp the max feed rate is
> reached! During a job is when the speed seems to be lower. also, my max
> feed rate seems low only 600-800mm/s due to current motor and driver setup.
>
> Could it be during the job the travel distances are much shorter so top
> speed will never be reached? Could I increase the acceleration settings
> in the duet config to improve speed on short travels? Just noting
> thoughts and actions to try tomorrow.
>
> I will definitely look into upgrading my XY motor setup to increase that
> 600-800 mm/s limit.
>

> *running generic dc servos for the XY with the duet3 6xd *and the z,u,v

> and a,b,c rotation motors are on a duet3 6hc. Thinking about upgrading
> to clear path servos for the XY for more speed.
> On Wednesday, October 22, 2025 at 5:35:38 PM UTC-7 Fern528 wrote:
>
> Hello everyone,
>
> I noticed that the speed while OpenPnP controls my duet controller
> is less than the speed if I run the machine via the web control at
> max feed. I assume it has to do with the driver settings for the
> motion planner. As of now I switched to EuclideanAxisLimits with max
> speed set to 0 per the GcodeAsyncDriver · openpnp/openpnp Wiki ·

> GitHub <https://github.com/openpnp/openpnp/wiki/
> GcodeAsyncDriver> this still runs slow. I also set my jerk in the

> axis settings to a ridiculous high number and that initially helped
> the speed dramatically from the snail motion it was doing initially.
> Those are the two settings I have changed to improve the speed.
> currently thinking about upgrading the motors to push the duet max
> feed even higher and if openpnp is less then maybe then it will run
> at a decent speed.
>
> Question: does the backlash comp. affect the feed rates?
>
> If anyone has worked with duet boards and OpenPNP any advice is
> appreciated.
>
>
> Thanks, Fernando
>

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[Fernando Corona]

Thank you Jan! 

I will try this out today. 

- Fernando

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