cmg...@sover.net wrote: >Peter > >Your explanation makes perfect sense, and was my first "guess". But my >mind says such an "accumulator" must wait for process. There must be gaps >in my understanding. > >Sebastian's description/explanation allows for "projection" of motion >commands by reading the g-code destinations (my question of where is this >reader remains)and letting the oscillator send pulses to the motor >drivers. > > The interpreter runs in userspace, and determines what motions are needed. This may not be exactly what's programmed, for example an arc may be inserted between two lines when using cutter compensation on the "outside" of the G-code path. These are the canonical commands that Sebastian mentioned. These commands are passed to the trajectory planner, which runs in the realtime kernel.
>Are step and direction "pulses" present at the parallel port just ignored >in this system of "Mesa Cards and Hostmot2" ? > > There are no step and direction pulses on the parallel port with a Mesa system. If you're using the parallel-connected 7i43 card, the parallel port is only used to read and write the registers on the FPGA. >What system handles pulse duration and direction hold time? Is that all >in the FPGA or is EMC2 in control via the ini files? > > The trajectory planner calculates the next position on the path at a 1 kHz rate (by default). Since velocity is distance / time, and both the time interval and the distance are known, a velocity can be calculated. In the case of step generators, this is reduced to the number of steps per second, which is sent to the FPGA. The FPGA then outputs steps at that rate until a new step rate (velocity) command comes along the next cycle. >I think I should have a look at the configuration files of a "straight" >setup, and one that uses the HostMot2 config. > > They won't tell you very much, except that the parallel port driver isn't used in a Hostmot2 config. >I hope this is not all a bother to you. >This is helping me ! Thanks > >Cal Grandy > > Everyone's got to learn somehow :) - Steve ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
