On Oct 17, 2011, at 9:07 AM, andy pugh <bodge...@gmail.com> wrote:
> On 17 October 2011 13:40, Tom Easterday <tom-...@bgp.nu> wrote: > >> We have tried many combinations of max_acceleration and max_velocity for >> both EMC (TRAJ section) and in the Axis (Y in our case) we are jogging. The >> last settings we were using are pastebin'd below - but keep in mind we have >> tried a wide range of values. > > One thing I notice is that you only have one setting for > MAX_ACCELERATION in the INI file, this is shared between the motion > planner and the stepgen. This could be the problem. > Normally a stepper-based configuration will use a > STEPGEN_MAX_ACCELERATION (or similar) tag to give the stepgen a bit of > extra headroom over the trajectory controller. All your INI file > changes have been changing both values at the same time. > I noticed that last night as well and tried using MMAX_ for both accel and vel but it made no difference. > It is worth clarifying what "following error" means in the case of a > stepper system, without feedback. What is indicates is the difference > between the number of step pulses that have been requested relative to > the number that have been output. The normal cause of a disparity in a > parallel port system is that the base thread isn't quick enough to > actually make the pulses. In a Mesa system this is unlikely to ever > happen. However, you also see a problem if there isn't any daylight > between the motion controller limits and the stepgen limits. > Understood. We have tried so many combinations now that I know we have not pushed the envelope in all cases. We are not running a base thread, just a servo thread at 100000 ns. And as an aside I cannot configure the servo thread down lower than 750000 ns or I get realtime errors on startup of EMC. This too seems like a bug. But one thing at a time... > Can I suggest you hand-edit the values in lines 247 and 248 of you HAL > file? (Or, alternatively, add a new tag to the INI file stanza and use > that) Not in front of it at the moment so not sure what lines these are but will look in a bit... > > Do you actually see the overshoot-and-return in Halscope without the > drive attached, or just the f-error? Yes we see overshoot and return. Tom > > -- > atp > "Torque wrenches are for the obedience of fools and the guidance of wise men" > > ------------------------------------------------------------------------------ > All the data continuously generated in your IT infrastructure contains a > definitive record of customers, application performance, security > threats, fraudulent activity and more. Splunk takes this data and makes > sense of it. Business sense. IT sense. Common sense. > http://p.sf.net/sfu/splunk-d2d-oct > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2d-oct _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
