On Mon, Jul 27, 2015 at 11:54 AM, John Kasunich <jmkasun...@fastmail.fm> wrote: > > In principle, making things more modular is always good and welcome. > But in practice, the technical feasibilty does come into play. If the only > way to pull screw comp out of motion is to add several more HAL pins > to motion so that the screw comp module can be aware of motion > internals, then perhaps it shouldn't be pulled out. > > Agreed. If it become a spaghetti mess, then it probably doesn't make sense to do. I would be willing to go down the rabbit hole without know for certain everything will work out. If turns out to be a dead end, then its only my loss.
> Referring back to the block diagram, I can see one specific issue that > would > need to be resolved: > > See the box labeled "motor offset", which is summed with the screw comp > output? That value is determined during homing and stuffed into that box > by the homing routine. It needs to be added to output (and subtracted from > feedback) on the motor side of the screw comp block, so that screw comp > knows the absolute axis position, not the more-or-less "random" motor > position. > (Motor position varies depending on where the axis was when the power was > turned on.) > > Couldn't that be left alone? Unless there is a finer technical detail here I'm missing (I haven't studied it too much yet), I think motor offset addition could be left in place. Another implementation detail is how to get the screw comp data to the > compensation component. Realtime HAL components don't have a clean > way to access files (such as a file that contains a screw compensation > curve). > Motion gets a variety of data from user-space already, and the screw comp > data piggybacks on the same data structures and user/realtime communication > link. A stand-alone screw comp component would have to solve that problem > another way. > This could be a major issue. I haven't looked at any of that yet, and I don't know much about it. Does anyone else have any thoughts to add about this? Brian ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
