John Kasunich wrote: > Richard Arthur wrote: > >> John Kasunich wrote: >> >>> Richard Arthur wrote: >>> >>> >>>> Issue: >>>> The direction of searching for the index seems to be the inverse of the >>>> direction of THE_HOME_LATCH VEL when I would have expected it to be the >>>> same. >>>> >>>> What I did: >>>> Update from (Ubuntu) 2.1.6 to 2.1.7. Generate new configs in my home >>>> folder and modify to suit. >>>> >>>> However, with the current set up, homing is achieved successfully on >>>> the index pulse as can be seen from the screen shot: >>>> >>>> http://imagebin.org/9711 >>>> >>>> ini snip: >>>> >>>> [AXIS_0] >>>> >>>> TYPE = LINEAR >>>> HOME = 0.0 >>>> MAX_VELOCITY = 4.0 >>>> MAX_ACCELERATION = 20.0 >>>> BACKLASH = 0.000 >>>> INPUT_SCALE = 20000 >>>> OUTPUT_SCALE = 1.000 >>>> OUTPUT_OFFSET = 0.0 >>>> MIN_LIMIT = -32.0 >>>> MAX_LIMIT = 20.0 >>>> FERROR = 0.01 >>>> MIN_FERROR = 0.01 >>>> HOME_OFFSET = 0.0 >>>> HOME_SEARCH_VEL = 0.1 >>>> HOME_LATCH_VEL = 0.04 >>>> HOME_USE_INDEX = TRUE >>>> HOME_IGNORE_LIMITS = YES >>>> MAX_OUTPUT = 10 >>>> >>>> Thank you. >>>> >>>> Richard >>>> >>>> >>> Thanks for the halscope shot - that helps a lot! >>> >>> It looks like you are starting the homing process already on the switch. >>> (Or maybe the home switch is active low and EMC only thinks it is on the >>> switch.) >>> >>> Your search and latch velocities are both positive. But EMC starts the >>> homing process moving in the negative direction - it thinks its on the >>> switch and is trying to back off. At about 3.5 divisions on the scope >>> trace it thinks it is off the switch and starts to move positive at >>> search velocity. It almost almost immediately hits the switch, then >>> backs off at a negative velocity. It begins the final pass at positive >>> latch velocity just after 4 divisions on the scope trace. >>> >>> What physical direction corresponds to the initial negative slopw >>> portion of the scope trace? Which end of the axis is your switch on? >>> Is that initial move toward or away from the switch? >>> >>> If your switch is active low, you can invert the input by connecting >>> to "m5i20.0.in-<whatever>-not" instead of "m5i20.0.in-<whatever>". >>> >>> Regards, >>> >>> John Kasunich >>> >>> >> I've increased the Home_Latch_Vel to 0.8 to enable me to squeeze in the >> whole cycle with 4 channels. This latch vel causes problems with >> 'bouncing', so it is just to make my point. Screen shot here: >> >> http://imagebin.org/9716 >> >> The servo amps switch off travel at the limit switches (as previously >> discussed) and home/limit is shared. As I see it, slope 1 is the >> Home_Search_Vel, 2 is backing off, 3 is Home_Latch_Vel., 4 searching for >> index. My point is that after final detection of switch, the direction >> is reversed to find the index. As I said at the beginning, this is not >> what I expected - maybe I'm wrong? >> >> I've got no problem with homing. Under 2.1.6 I used the 2nd homing >> sequence diagram successfully (as this screen shot, but after slope 3, >> Home_Offset -0.1) and as this shot shows, I can home on the index now. >> It's just that homing using the index doesn't appear to behave as >> detailed in the homing sequence diagrams of the user handbook. I've not >> answered you questions directly, in the hope that the 4 ch. screen shot >> makes it clear. >> >> Thank you. >> >> > > I was interpreting the picture as: > slope 1 = move negative to get off switch > slope 2 = move positive to find switch (normal search phase) > slope 3 = back off switch before final move > slope 4 = move to switch at latch vel, then continue till index pulse > > Assuming that the home switch input is the same as the neg limit switch > input, that interpretation doesn't make sense. > > Your original post showed an ini file with positive values for search > and latch velocities. If slope 1 is search and slope 3 is latch, that > doesn't make sense either. Those slopes are clearly negative in spite > of the positive values in your ini file. Any bug that severe would have > shown up long ago. > > Fortunately there is a way to see exactly what is going on. > > Can you re-do the test and post a new image? Set the green channel > to 'axis.0.home-sw-in' instead of 'axis.0.neg-limit-sw-in'. They are > probably the same, but its best to be sure. Set the dark blue channel > to 'axis.0.home-state' instead of 'axis.0.homing'. Set the scale for > 'home-state' to 5 per division - home-state is an integer that ranges > from 0 to 20 during the homing process. To understand what the values > of 'home-state' mean, , search for "states for homing" in > http://cvs.linuxcnc.org/cgi-bin/cvsweb.cgi/emc2/src/emc/motion/motion.h?rev=1.71.4.3 > > Looking at home-state will tell us exactly what is going on during each > slope. If there is a bug, we'll find it and fix it. Likewise, if there > is a misconfiguration somewhere, we'll fix that. > > Can you post your complete ini and hal files at pastebin.ca when you > post the next scope trace? > > Thanks, > > John Kasunich > > ini: http://www.pastebin.ca/644773 hal: http://www.pastebin.ca/644774 screen shot: http://imagebin.org/9721
Thanks, Richard ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
