The google group fell off the reply. For completeness done manually :) > On 22 Feb 2020, at 17:44, Bas de Bruijn <[email protected]> wrote: > > > > >>> On 22 Feb 2020, at 15:25, John Allwine <[email protected]> wrote: >>> >> Hi Bas, >> >> Thanks for your suggestion! I’ll definitely look into writing a custom >> component rather than a custom MachineKit build. >> >> I’m afraid, though, that I don’t completely follow the rest of your >> suggestion. Could you please expand a little? I have used immediate mode >> before. Let’s say a user clicks a home button in the Axis GUI. How could I >> tie into that event to start the process? Alternatively, if I created my own >> button to trigger something in Hal, how would I trigger immediate homing? >> How would you recommend setting the position on the rising edge? > > You might not have to do anything. I’m not an expert on the cnc stack. > If you have wired the enable pin of the motor physically and in HAL to the > enable pin of the motion component, then pressing the home button in the GUI > should start homing. Thus moving towards the end of your guide/motor. > Make sure you wire the smart pin to the home Hal pin. > Would that not work out of the box? > Does the special pin stay high after homing? > >> >> I believe I have a good grasp on how Hal works, but my knowledge of the >> built in components is limited. >> >> Thanks again for the help! >> >> John Allwine >> Owner of Allwine Designs >> https://www.allwinedesigns.com >> >>>> On Feb 22, 2020, at 1:04 AM, Bas de Bruijn <[email protected]> wrote: >>>> >>> >>> >>> >>>>> On 21 Feb 2020, at 23:30, John Allwine <[email protected]> wrote: >>>>> >>>> >>>> I'm looking into using Teknic SDSK servo motors with MachineKit. The SDSK >>>> models accept step and direction pulses like a stepper motor, so using >>>> hal_pru_generic's stepgen is straight forward. The major issue I see is >>>> attempting to use Teknic's precision homing routines, as it doesn't fit >>>> into MachineKit's limit switch routines. I'd really like to use their >>>> homing routine because it is accurate to less than 1/10,000 of an inch in >>>> my setup, which could be difficult to achieve using my own limit switch >>>> setup. It seems to me that in order to do so would require either a custom >>>> homing routine implemented in C++ (so a custom build of MachineKit). Any >>>> thoughts on this would be appreciated! >>>> >>>> The Teknic motors have 3 control pins and 1 feedback pin: >>>> >>>> Control Pins: >>>> Enable - Used to enable/disable the motor and plays a part in initiating >>>> the precision homing (see below). >>>> Step - Same as for a stepper motor >>>> Direction - Same as for a stepper motor >>>> >>>> Feedback - They refer to this as the HLFB (high level feedback) pin. Can >>>> be set to a number of different options, but the relevant one for homing >>>> would be ASG (all systems go) Position, which is high when the motor is in >>>> the commanded position, low while moving. >>>> >>>> The precision homing sequence is initiated as follows: >>>> >>>> 1) Put the motor into homing mode by toggling the enable pin on (if it's >>>> already on, then turn it off, then back on). >>>> 2) Command the motor with step and direction to move the joint to a hard >>>> stop. >>>> 3) The motor will detect the hard stop and stop accepting step pulses >>>> until it is commanded to go the opposite direction. >>>> 4) After the hard stop is detected the motor will back off to a precise >>>> location a configured number of internal encoder counts away. >>>> 5) After a configured number of milliseconds (default is 10), the HLFB pin >>>> asserts indicating that homing is complete. >>>> >>>> The hard stop detection and precision homing is fantastic. After the first >>>> homing sequence, the motor will return to a very precise location as long >>>> as the hard stop stays within ~2mm. I can physically put a shim (less than >>>> 2mm thick) in front of the hard stop and it still goes to a precise >>>> location that properly ignores the shim (so wearing on the hard stop over >>>> time doesn't affect the precision of the homing sequence). >>>> >>>> So, does anyone have recommendations for how to perform this sequence >>>> properly in MachineKit? Preferably, I'd avoid needing a custom build of >>>> MachineKit, but if it's required to make homing a simple click of a button >>>> then I'll have to go that route. >>> >>> Hi John, >>> >>> So if I understand correctly your homing sequence is started on the rising >>> edge of the enable pin. >>> >>> Then you need to move to your chosen homing side. >>> Your homing is done when the special pin rises. >>> >>> Maybe all parts are already there. >>> Have you tried configuring as ‘immediate’ homing? So rising special pin >>> sets the position? >>> http://www.machinekit.io/docs/config/ini_homing/ >>> >>> Even if you decide you need a special component, you do not have to rebuild >>> MK, just write the comp in C and install with instcomp. >>> >>> http://www.machinekit.io/docs/hal/instcomp/ >>> >>> Best, >>> Bas >>> >>> >>>> -- >>>> website: http://www.machinekit.io blog: http://blog.machinekit.io github: >>>> https://github.com/machinekit >>>> --- >>>> You received this message because you are subscribed to the Google Groups >>>> "Machinekit" group. >>>> To unsubscribe from this group and stop receiving emails from it, send an >>>> email to [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/machinekit/6b01a405-251f-4633-af72-abbcd6c78ab0%40googlegroups.com. >> >> -- >> website: http://www.machinekit.io blog: http://blog.machinekit.io github: >> https://github.com/machinekit >> --- >> You received this message because you are subscribed to the Google Groups >> "Machinekit" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/machinekit/7E019B91-0888-4BE4-8F65-1F22B40EC7C6%40allwinedesigns.com.
-- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/machinekit/AF5F99D8-0415-4041-9DBB-0D54AC22525D%40basdebruijn.com.
