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Re: [mach1mach2cnc] Mach 4 update

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  • Dave
    Hi Sergey, Could you define the acronyms DDA and PVT for the rest of us mere mortals. I thought that the Galil boards interface was only a time and position
    Message 1 of 122 , Aug 2, 2013
      Hi Sergey,

      Could you define the acronyms DDA and PVT for the rest of us mere mortals.

      I thought that the Galil boards interface was "only" a time and position
      buffer feed.

      If not, what boards are you referring to??

      Dave

      On 8/1/2013 3:07 PM, Sergey Kubushyn wrote:
      >
      > On Thu, 1 Aug 2013, Brian Barker wrote:
      >
      > Would you translate it to plain English please?
      >
      > What does "change on every call" mean? You used to have a circular
      > ring for
      > fixed data so the controller just pulls data from that list. So what does
      > that "change on every call" mean for this scenario? Or it is something
      > different this time around?
      >
      > Then, DDA and PVT are the same thing like frequency and period. You can
      > easily convert PVT data to DDA and vice versa with a trivial math.
      > Velocity
      > difference at the beginning and end of each PVT value divided by time
      > gives
      > you acceleration and so on. If DDA didn't work how PVT is supposed to?
      >
      > Once again, does "DDA thing never worked out" mean that Galil plugin you
      > were giving source code for never worked? So what data did the WORKING
      > Galil
      > plugin use?
      >
      > And what does "will be able to get real PVT data" mean? Is it going to be
      > documented? What hoops should I jump to get that data so I'd be able to
      > interpolate with my own DSPs and provide the step rate I want or feed
      > intellectual servo drives with totally different set of commands, not
      > Dir/Step?
      >
      > > At this time it is fixed... But we could make it so you can change it on
      > > every call. The DDA thing never worked out.. but you will be able to get
      > > real PVT data if you would like.
      > >
      > > Thanks
      > > Brian
      > >
      > >
      > > On 8/1/2013 2:05 PM, Sergey Kubushyn wrote:
      > >> On Thu, 1 Aug 2013, Brian Barker wrote:
      > >>
      > >> I hope we will get PVT/DDA trajectory data, right? That is _ABSOLUTELY_
      > >> necessary to design a decent motion controller... "Next position at
      > fixed
      > >> time slice" is not any good at all.
      > >>
      > >>> Hello Chuck,
      > >>> I do! Mach4 and its screen designer are working well at this time.. we
      > >>> have been testing with an OEM for a few months now and finding lots of
      > >>> little things that we missed. Now we are trying to get some docs done
      > >>> for the API interface. As soon as that doc is done it will be open to
      > >>> the plugin authors so we can get all the hardware working that you are
      > >>> using now :). We need to make the "stock screen" and I have no idea
      > >>> what that is going to look like at this time :( . Once we have that
      > >>> stock screen we can start to make the operations manual so
      > everyone can
      > >>> start using it. If everyone is okay without a manual to run the
      > software
      > >>> it will take less time.. the manuals take lots of time to make :(
      > >>>
      > >>>
      > >>> Thanks
      > >>> Brian
      > >>>
      > >>> On 8/1/2013 5:50 AM, chuckels431 wrote:
      > >>>> Brian,
      > >>>> I know you're dreading someone bringing this up :) but do you
      > have any update on Mach4 progress?
      > >>>> Chuck
      > >>>>
      > >>>
      > >>> ------------------------------------
      > >>>
      > >>> www.machsupport.com - Web site AccessYahoo! Groups Links
      > >>>
      > >>>
      > >>>
      > >> ---
      > >> ******************************************************************
      > >> * KSI@home KOI8 Net< > The impossible we do immediately. *
      > >> * Las Vegas NV, USA< > Miracles require 24-hour notice. *
      > >> ******************************************************************
      > >>
      > >>
      > >> ------------------------------------
      > >>
      > >> www.machsupport.com - Web site AccessYahoo! Groups Links
      > >>
      > >>
      > >>
      > >>
      > >
      > >
      > > ------------------------------------
      > >
      > > www.machsupport.com - Web site AccessYahoo! Groups Links
      > >
      > >
      > >
      >
      > ---
      > ******************************************************************
      > * KSI@home KOI8 Net < > The impossible we do immediately. *
      > * Las Vegas NV, USA < > Miracles require 24-hour notice. *
      > ******************************************************************
      >
      >



      [Non-text portions of this message have been removed]
    • Spencer Chase
      wouldn t you use a switch with an arm that was arranged so it could overtravel without damage? i have some microswitches that are pretty well made with rollers
      Message 122 of 122 , Mar 3, 2015
        wouldn't you use a switch with an arm that was arranged so it could overtravel without damage? i have some microswitches that are pretty well made with rollers on the end of an arm. they do not have a lot of slop in them and they are snap acting and maybe repeatable?

        since i am not cutting ferrous metal is there any reason to not use the hall effect switches?that are already installed and working?  i think they are very repeatable as long as the reference tab does not flop around. the X axis is on a long floppy arm which i think is the original way it was as an Emco machine. there is a little room for a brace to stiffen it.

        On 3/3/2015 7:35 AM, Hannu Venermo gcode.fi@... [mach1mach2cnc] wrote:
         

        You would not care.
        Also, you need to make sure you dont overtravel into the switch.

        On 03/03/2015 16:19, Spencer Chase lists@...
        [mach1mach2cnc] wrote:
        > if you hit a limit, isn't it pretty much time to reset? why would you
        > care if you were off by a few mm, you probably screwed up if you hit
        > the limit anyway?
        >
        > i am wondering about all this because i do want to do proper limit
        > switches on my machine at some point so i can home reliably. i will
        > probably stick with the hall effect switches if i can stiffen up the
        > arm that the X axis limit switch uses but if i do use microswitches i
        > might want to debounce them? since mach3 does software debouncing it
        > is probably not a good idea to add another possible point of trouble.
        > i use software debouncing in all of my arduino machines and it works
        > just fine and is very configurable.

        --
        -hanermo (cnc designs)


        -- 
        
        Best regards, Spencer Chase
        67550-Bell Springs Rd.
        Garberville, CA 95542 Postal service only.
        Laytonville, CA 95454 UPS only.
        Spencer@...
        http://www.spencerserolls.com
        (425) 791-0309
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