I think as long as you're modeling your extruder as an axis, you can't change it's speed without also changing the speed of all the other axes (by using the feed override knob on the motion controller).
Also, as long as your extruder's position is controlled by the motion controller, you won't be able to change its scale factor without causing a following error. You might be able to short-circuit the motion controller's notion of the A axis by netting the motor-pos-cmd back in to motor-pos-fb, then eavesdrop on what the G-code says the extruder should be doing by connecting the motor-pos-cmd net to some more hal circuitry. For example, you could run it into a ddt component (to get the g-code's commanded extruder speed), run that into a scale component, and finally run the output of scale to your extruder's stepgen's velocity command input. Then by tweaking the scale.gain pin you would tweak the actual extrusion rate. It might work! On Jan 18, 2012, at 13:41 , Lars Andersson wrote: > I would like to dynamically change the flow rate of material feed of my > plastic rapid prototyper. The material is dispensed by a step motor on the > A-axis. A is running proportional to the combined speed of X and Y (always > counting up) . The scale factor for A is set at the G-code generation, it is > almost on target but I would like to tweak it slightly. So I try to change > stepgen.3.position-scale with a potentiometer. > > > > net flowrate stepgen.3.position-scale <= input.0.abs-rx-position > > This is not allowed, "stepgen.3.position-scale" is a parameter, not a pin > > > > I try manually while running: > > setp stepgen.3.position-scale 210 (it was was 200 before) > > This immediately gives a "joint 3 following error" even for a very small > change. > > > > Can I work around this? > > > > Is there a better way to do what I want to do? (Hope so!) > > > > ------------------------------------------------------------------------------ > Keep Your Developer Skills Current with LearnDevNow! > The most comprehensive online learning library for Microsoft developers > is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, > Metro Style Apps, more. Free future releases when you subscribe now! > http://p.sf.net/sfu/learndevnow-d2d > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- Sebastian Kuzminsky ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
