Thank you Michael. Once upon a time (6/22/2009), I suggested: ==============
One way to approach this would be to use HAL to add a position offset to each joint. Normally, this would be set to zero. While paused, one could then have jog functions that changed those offsets. That could manually position the cutter where you wanted. Then when you are done, use the jog functions to get back to where you started (all offsets zero). Then hit continue. Notice that no MDI functions would be used. Coolant, etc would be unchanged. You would probably want a manual coolant switch to turn off the coolant. ============== I still believe that would be the way to go. (Although I would add some more automation.) A new HAL component could connect to N jog inputs (one for each axis). In feed hold mode, the joggers would become active. The new component would pass the jogs as offsets to the various axes and *memorize* the jogs in the order that they occurred. When the user was done clearing swarf or whatever, he could then push a special resume button. That would cause the new component to play back the jogs in reverse. The tool would move back to where it originated, and the program could be resumed. Since memory is cheap, an arbitrary path could be memorized at little cost. Coolant settings, etc, could also be memorized, changed, and restored. I think this would be pretty simple to implement. It requires one new component and a bunch of HALfu. Regards, Ken _ _ On 4/24/2012 6:27 PM, Michael Haberler wrote: > Am 24.04.2012 um 21:00 schrieb andy pugh: > >> On 24 April 2012 18:53, Michael Haberler<[email protected]> wrote: >>> I decided to ignore the conventional wisdom that it cannot be done, and >>> gave it a try. >> To be fair, it was only ever described as "hard" not "impossible" and > yes, but 'impossible' sounded infinitely better in the feature pissing > contest;) > >> I think you have made some changes to the underlying structure? > The basic idea is to snapshot a motion queue state on 'retract', including > current position within a move, and switch to an alternate motion queue where > you can do arbitrary moves, like the retract or recovery move. On 'recover', > when you are where you left off, switch to the primary queue, and continue. > Currently task doesnt even notice that something happened, it's all just a > motion which tooks it tool a long time to complete. The whole thing assumes > coordinated mode and remains in it. > > I think jogging can be sled in without much damage. For the bigger picture, > one could take the 'keep this completely isolated within motion' or 'make > task aware of it' views. Not sure yet. > >> Is changing the tool length possible when retracted. or does that >> invalidate the original queue? > This would be nice but cant be exclusively solved at the motion level right > now; I just discussed this with Chris on linuxcnc-devel irc. > > The issue is that offsets are currently applied during interpreter runs in > the canon layer; once they reach task and motion everything's said and done > wrt offsets; changing it there to compensate against the earlier decision is > bound to be a hit-and-miss game. > > However we agreed this is too early, and moving offsetting to the task/motion > area would help. That means offsets would be applied in motion, and could be > changed there. Once that is done, that should be possible. I dont think it is > that hard, but some aspects I dont understand yet, like how rotation would > fit in. > > It also affects how tool information is used (aka 'who sees what'): the > interpreter starts out with some view of tool information, then proceeds; > then motion might change some offsets; then interpreter mght continue as it > was held up by queue full. It needs to be clearly thought through and spelled > out. This was no issue so far. > > - Michael > > >> -- >> atp >> The idea that there is no such thing as objective truth is, quite simply, >> wrong. >> >> ------------------------------------------------------------------------------ >> Live Security Virtual Conference >> Exclusive live event will cover all the ways today's security and >> threat landscape has changed and how IT managers can respond. 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