> Because you still have the random latency of the usb involved. The machine USB latency isn't random in ISO transactions, its pretty precise. > could overshoot 20 thousandths of an inch while the command to stop that > axis, and start moving another was in the pipeline. This is all in the > specs for usb. If you are trying to hit sub 1mS deadlines on a PC you are in the wrong game, you can get stalls that big on the bus off the graphics card, off all sorts of things. > Figure that out so that USB can actually be used, and there are quite a few > folks on the emc-user list that will bow and scrape when you walk into the > room. It is a very common question from the new bee's, and one we have to > explain to them all, one by one. > > If indeed, there was a usable solution made available, we would be more > than happy to put it in our wiki, and point the new bees to it. The robotics people handle this all fine - but they use reasonable smart controllers so they don't have a PC playing "I am a very expensive and completely crap microcontroller" Or take a look at reprap .. 8) -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
