Step, Dir, Enable Breakout

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  • October 1, 2013 at 7:32 pm #4675
    InPhase
    Member

    Tail
    What I have labeled there is the tail I was referring to earlier. If I run this under Mach3 on my machine or someone else’s it is fine. If I run it under Coolterm using the dev branch with TinyG it is fine.

    If I run it under edge or master branch using Coolterm or tgFX, I get what you see in that picture. And I mean identically. At first I thought I had a mechanical issue. Then I checked for electrical problems with grounding and shielding. Then I changed the type of gcode the design software produced. Then I scanned the gcode line by line looking for a problem.

    Other gcode files also run somewhat askew as well, but that Ford logo became my default test file. This is the result from dev branch:

    Good

    • This reply was modified 11 years, 1 month ago by InPhase.
    October 1, 2013 at 7:36 pm #4677
    InPhase
    Member

    My point is, how is it a gcode issue if it will run everywhere but edge and master? But when all was done, the graphic on the tgFX screen proudly displayed a perfect picture but the wood under the spindle was like Congress.

    Alas, it matters not because I’ll be out of the game for a bit.

    • This reply was modified 11 years, 1 month ago by InPhase.
    October 21, 2016 at 11:29 am #9975
    Keith-W
    Member

    I realize this thread is very old but I’d like to add to it anyway in hopes of getting a reply.

    Regarding the exposed signals on headers for the four motors, would it be possible to use “enable” to bypass, override, or work in combination with the existing code? I was hoping to add a key switch that would enable the motors when allowed. If the processor ties the enable to ground in order to assert enable but already has a pullup, is there any reason why I can’t add another external pullup and the key switch without any processor code change? Also, does the existing code read the state of enable as well as write to it in order to see if the necessary state was reached?

    October 27, 2016 at 9:01 pm #9989
    Keith-W
    Member

    Bump

    Has anyone used the “enable” line with an external switch?

    This doesn’t appear to be a very active forum … someone please prove me wrong

    October 28, 2016 at 6:29 am #9991
    cmcgrath5035
    Moderator

    Forum – Not as active as some other related forums, such as Chilipeppr, Ox and others.

    Your query about Keyswitch is a bit unclear to me – when you Say “I was hoping to add a key switch that would enable the motors when allowed.”, Allowed by what? Do you mean the key switch?
    Would you install one keyswitch per motor?
    Is your objective to force motors ON, irrespective of logic (the tinyG state machine) or provide a lockout function, keeping Motors disabled unless keyswitch was in proper position?

    The Step-Dir-Enable interface is intended to drive external steppers.
    Enable is a logic output, active low.
    I don’t believe you can backdrive the Enable Ports, if that is your question.

    I assume you have looked at the Schematics?

    October 28, 2016 at 8:19 am #9992
    Keith-W
    Member

    The use of the key switch would enable/allow motion for all axis as an additional layer of safety. So yes, a lockout function. I did look at the schematics but didn’t notice that the enable was an output. There may not be another way to do this with this board since there is no dedicated input.

    Since all logic on the board is powered by Vmot and not USB power that doesn’t appear to be an option either.

    Looks like I may have to leave this feature out unless you or others have a suggestion.

    Thanks for the reply!

    October 28, 2016 at 6:48 pm #9993
    cmcgrath5035
    Moderator

    I don’t see a way to “lockout” the on-board stepper drivers with a mechanical switch.
    As you note, interrupting Vmot would cause a tinyG reset.

    You could use the $md command to disable all motors, but that is logical

    October 28, 2016 at 10:01 pm #9994
    Keith-W
    Member

    The only other thing I can think of would be to use to use a DPDT relay on each motor output (for each coil pair). I doubt I’ll do this now but maybe a feature suggestion would be to have a some configurable inputs for functions like this.

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