On Sun, 10 Aug 2008, Jim Coleman wrote: SNIP___________________________________________________________________ >> >>> Also, what do I need to add in the hal and everything to enable an >>> index on the encoders? I'm thinking I can see if it is missing counts >>> if I have an index to reference. >> >> I think you would need to write a custom component that reads the >> software decoder counter on the first index trigger and then compares >> that with subsequent counts on index to see if they happen on multiples >> of encoder counts per rev. I wouldn't mind seeing more background error >> checking of hardware subsystems.
This brings up a real hazard here: If you get going so fast you miss counts with your software encoder counter, you can lose control of your servo. Index pulses tend to be short so they may disappear at the same time. Normally I would expect this set of circumstances to throw a FE, but I would not trust my life or even a small appendage to this always happening. Servo runaway can also happen with hardware failure in ways that will not throw a FE ( say a broken encoder wire+ an integral term in the PID loop...), so I think its good to have some kind of excessive drive detection (maybe as simple as detecting full drive for 20 or so samples in a row) >> >>> I hope all of this makes sense, its been a long day and I'm excited >>> I've actually made a little progress. >>> >>> Thanks guys, >>> Jim Coleman >> >> Are you doing more than one project? I thought you where well along on a >> mill conversion. Could you give us a summary of what you are doing? >> >> -- >> Kirk Wallace (California, USA >> http://www.wallacecompany.com/machine_shop/ >> Hardinge HNC/EMC CNC lathe, >> Bridgeport mill conversion, doing XY now, >> Zubal lathe conversion pending >> Craftsman AA 109 restoration >> Shizuoka ST-N/EMC CNC) >> >> >> ------------------------------------------------------------------------- >> This SF.Net email is sponsored by the Moblin Your Move Developer's >> challenge >> Build the coolest Linux based applications with Moblin SDK & win great >> prizes >> Grand prize is a trip for two to an Open Source event anywhere in the world >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >> _______________________________________________ >> Emc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
