Hi Nick,
 
   As the current system stands, if you want to get rid of the hunting on 
the DIR lines then it seems you need the PID loop.
   or...
   If you want to get rid of the necessity to use the PID code, you can 
modify the PRU code that generates the step pulses.

   The original EMC system MachineKit is based on was not a stepper centric 
system, rather a servo based system that used encoders for position 
feedback.  Later modifications were added to allow steppers and when the 
system migrated to the BBB, the PRU code  (which is run on another 
processor inside the chip) was added to generate step pulses.  The complex 
communication between the several internal processes (running independently 
and at different rates) has lead to a situation where the problem with the 
hunting occurs.  For a diagram of the different processes, look here:

http://www.machinekit.io/docs/hal/rtcomps/#sec:Stepgen

Jeff

On Thursday, May 11, 2017 at 5:08:33 AM UTC-7, Nick Collier wrote:
>
> @Alexander Rössler 
>
> I am new to Machinekit. I don't think I have that Python file. In lib I 
> don't have any python directory. I can't seem to find an fdm directory on 
> my system. 
>
> I just have a fresh install of this image with no modifications. 
>
> https://rcn-ee.com/rootfs/bb.org/testing/2017-02-12/machinekit/bone-debian-8.7-machinekit-armhf-2017-02-12-4gb.img.xz
>  
>
> Btw why do I need a PID loop with a stepper motor? Could I not just remove 
> the PID loop? 
>
>

-- 
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