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Hi community of LinuxCNC,

I have two questions about linux cnc. The first is that if is posible obtain a double-S velocity profile in LinuxCnc (I adjunt a image with curves for this profile) or other profile different to trapezoidal velocity profile. The second question is if is posible move two stepper to 2400rpm and control analog spindle voltage with a mesa 5i25 7i78 combo cards at the same time. The micro step for this motors is 10000 step per revolution and this system not have encoders resolvers or any feedback.

1. LinuxCNC generates trapezoidal profiles (second order).
There has been some work on S curve profiles but
I dont think it is anywhere close to being committed

2. There is no practical step rate limitation with the 5I25
(it can generate step rates to 8.333 MHz, this is 50,000 RPM at 10,000 steps per rev)
analog spindle control is independent and has no effect on step generation

I have found this video:
and in this say that it have double s curve velocity profile and the source to patch EMC2 is in github.com/araisrobo/linuxcnc but I dont know how I should be it patch to my linuxcnc.

diegoroman17 wrote:
They have moved all the motion onto the 7i43 FPGA, I think. So it is even more difficult than it might at first appear.

This is a fairly serious programming task. I think the Project would be happy to see someone pick it up and make it work, but it is not trivial, especially for complex kinematics.

Would appreciate if I can use Linuxcnc in the future with S curve profile at least for G0 moves (rapid and non-cutting) in order to reduce the vibration caused by the jerk.

I think I can handle this task. I have programmed the algorithm for double S velocity profile in matlab. For now I have to delve more into the programming of linuxcnc to implement this new profile.