The machinekit-fdm configs are also using the PID workaround.
https://github.com/machinekit/machinekit/blob/master/lib/python/fdm/config/base.py#L60

Charles Steinkuehler writes:

> On 11/5/2016 8:11 AM, Johan Jensen wrote:
>> 
>> _4. After completing the first jog command (+/- does not matter), the DIR 
>> signal 
>> starts to oscillate between 0V and 4V continuously. __Not expected._
>> 5. If I use "disable motors" in Machinekit the DIR signal stops oscillating 
>> and 
>> goes back to 0V.
>> 
>> Any ideas on how to correct this would be greatly appreciated. Thanks.
>
> This is "hunting" where the PRU driven step/dir generator is
> oscillating back and forth (by a fraction of a step) around the set
> position point due to the two asynchronous timebases (ARM CPU core and
> PRU stepgen) and the ARM interrupt latency/jitter.
>
> If this is causing you problems, you could add a deadband to the
> hal_pru_generic stepgen driver (PR welcome!), or switch to using a
> standard HAL PID control (with the PRU stepgen in velocity mode)
> instead of the fairly simplistic PID loop found in the hpg driver.
> There are some examples of configurations using the HAL PID + steppers
> for hostmot2 (Mesa) hardware, and I think there have been some for the
> BeagleBone if you dig through the group archives.
>
> A PR for an example BegleBone configuration using HAL pid components
> would also be welcome!
>
> -- 
> Charles Steinkuehler
> [email protected]


-- 
Alexander

-- 
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