Chris; I only would request B-Directional as a time saver. I had a HAAS 5C indexer which used stepper motors and it was reasonably fast - even so, indexing often was the largest portion of total program run time. For small indexers that most of us will make from small rotary tables, they will likely be driven by low end steppers. These cheap rotary tables are also notorious for having tight spots because the gear was not mounted perfectly concentric. As the home builder/ converter we have to go to the lowest common denominator and keep the max step rate down to where the motor has excess torque at the tightest area. Moving Negative 60 degrees is alot faster than moving 300 degrees. This is fine for a hobby user, but I earn a major portion of my income from production machine jobs. Some say time is money, but more importantly you can never buy more time. I have worked 20hr days to meet delivery deadlines and God as my witness you can look at me now and know I really needed that beauty slee p!
The remote cycle start and cycle ready/complete are function options on most commercial CNC machines - how they are used is up to the machine integrator. Same in LCNC.There is no specific LCNC code for this, but there are definable M codes and depending on your hardware will determine how you would configure this. LCNC would have no "Knowledge" of indexer position, only if its ready or moving. I guess you could add another output for home that could be used to verify that all moves in the cycle had completed properly. ( The sum of all incremental moves would bring indexer back to its starting point. ) You are also correct about the mechanics - every table seems to have its own individual custom requirements. A company I worked for bought 5 "identical" units and was intending to use a single servo to drive them all. Each one had bolt holes in different locations. I swear I think most Chicom machines are just free hand drilled with a drill press without even doing hole position layout. Greg ________________________________ From: Chris Albertson <albertson.ch...@gmail.com> To: Greg Bentzinger <skullwo...@yahoo.com>; Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> Sent: Monday, September 26, 2016 4:25 AM Subject: Re: [Emc-users] Rotary table indexer project This is the kind of ideas I was looking for. Two questions: (1) What does bi-directional get you that can't be done by going all the way around. Maybe it takes longer to rotate 360+ degrees? Is there any other reason? Technically it is very easy to run bidirectional but I could not see a reason. (2) I did not know about "remote cycle start input and a cycle complete" in LinuxCNC. Got a pointer to the documents? If it could be done with a TTL level pins then adding this is free. A serial interface is also easy to add. Does LinuxCNC have a way to send data? The hardest part of building this is the mechanics. Cutting metal has to be custom engineered for each rotary table. I can host the software and schematics on GitHub. On Mon, Sep 26, 2016 at 2:35 AM, Greg Bentzinger <skullwo...@yahoo.com> wrote: Chris; > >I would add a remote cycle start input and a cycle complete output that could >be optionally hooked into LCNC. > > >Likewise I would allow bi-directional positioning moves. Just add a small >overshoot value and and feed back into position to maintain consistent preload >in one direction. > >I would be very interested in duplicating your Arduino indexer controller as I >often have parts I need to cut a hex drive feature on. > >Thanks; > >Greg > > >------------------------------ ------------------------------ >------------------ >______________________________ _________________ >Emc-users mailing list >Emc-users@lists.sourceforge. net >https://lists.sourceforge.net/ lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
