On 13 July 2012 07:26, Hugh Wylie <[email protected]> wrote: > Having deleted MIN_VELOCITY parms and correcting the A-joint type to LINEAR, > the time lag (having resulted from very different velocity vector commands > to the 5i23) is eliminated.
I am very puzzled about why either of these has any effect. MIN_VELOCITY is a setting for the feed-override sliders in Axis. It doesn't matter what axis type the A axis is, as the position commands for that axis are not used. (your gantrykins HAL passes the position for Y to axis.3 / joint.3, line 58 in gantrykins.c ) There might, possibly, be some hard-coded assumption somewhere that joint.3 == axis-A, but there shouldn't be. Angular joints are not treated the same way by the motion controller as are linear ones, but both your steppers are Y and get the Y-axis position command. Having said that, the axis.1.motor-pos-cmd and axis.3.motor-pos-cmd values are not necessarily the same number, as homing offsets need to be calculated. I wonder if there is something odd going on in that phase? In summary nothing in [AXIS_3] should matter as you don't have a 4th axis. If it does, then something is subtly wrong. If I was writing a gantry config I think I would but the HAL parameters for both Y-joints in the [AXIS_1] section with duplicates for values which were not identical, for example: #******************** # Axis Y #******************** [AXIS_1] TYPE = LINEAR HOME = 0.0 FERROR = 50 MIN_FERROR = 20 MAX_VELOCITY = 133.33333333 MAX_ACCELERATION = 1 # these are in nanoseconds DIRSETUP = 5000 DIRHOLD = 5000 STEPLEN = 5000 STEPSPACE = 5000 STEP_SCALE_1 = -115.7491 STEP_SCALE_2 = 115.7491 (etc) I still think that you should increase the stepgen max accelleration. ie: INI: [AXIS_1] TYPE = LINEAR ... MAX_ACCELERATION = 1 STEPGEN_MAX_ACCELERATION = 1.2 HAL: setp hm2_5i23.0.stepgen.01.maxaccel [AXIS_1]STEPGEN_MAX_ACCELERATION > Has maximum step rate been graphed > against number of instances? I think that the modules run in parallel in the FPGA so there may be no interaction. I suspect that the processor load of a pwmgen is independent of frequency anyway. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
