Hi Rob, Thanks for taking a look! Perhaps this information could help you get a predictable case set up. While testing, I'm able to always reproduce the error -7 when my [AXIS_0]HOME_OFFSET is set to 2.7499, [AXIS_0]HOME set to 2.5 and a program that simply moves to 2.5 in X:
% G0 X2.5 % The error that is produced in /var/log/linuxcnc.log: user line can't have zero length! xyz start = 2.500000007435e+00,2.499999999910e+00,-2.559125863375e-10, end = 2.500000000000e+00,2.499999999910e+00,-2.559125863375e-10 -John On Thursday, January 24, 2019 at 12:33:02 PM UTC-7, Robert Ellenberg wrote: > > Hi John, > > I'm taking another look at this now, and seeing some weird behavior with > the example NGC file in LinuxCNC 2.7.x too (hits an acceleration violation > in the A axis around line 1600). I suspect that there is an issue with the > floating point comparisons as well, in particular since LinuxCNC handles > the case of rotary + linear motion differently than a pure rotary motion. > As such, a motion that has some rotary motion and a pathologically small > linear motion could be triggering the problem. I don't currently have a > machinekit build on my dev PC, but I will set one up and do further testing > in simulation shortly. > > Best, > Rob > > On Thu, Jan 24, 2019 at 10:26 AM <jo...@pocketnc.com <javascript:>> wrote: > >> Hey Robert, >> >> Have you had a chance to look at this any closer? We hit this error 100% >> of the time on the Pocket NC for specific values of various HOME_OFFSETs >> (our current solution is to tweak those values by .0001" until the error >> goes away). The error occurs immediately after pressing the run button on >> any program after homing the machine. Any jogging before running the >> program and it runs fine. I've done a little digging into the code base to >> see what could be causing the issue, but don't have a good enough sense of >> the overall flow of data. Any insights would be appreciated. I've located >> several floating point equality comparisons that would result in a more >> precise comparison than the 1e-20 the trajectory planner is comparing >> against, but haven't had any luck when changing from direct equality (or >> inequality) operations to a difference comparison (i.e. changing x == y to >> abs(x-y) < epsilon). >> >> Here are a few places I've tried adjusting: >> >> https://github.com/machinekit/machinekit/blob/1dfa0045ba95fd68e744826d684efa513cbffa97/src/emc/motion/control.c#L449 >> >> https://github.com/machinekit/machinekit/blob/1dfa0045ba95fd68e744826d684efa513cbffa97/src/emc/rs274ngc/interp_convert.cc#L2465 >> >> (and several other similar instances in that same file) >> >> https://github.com/machinekit/machinekit/blob/1dfa0045ba95fd68e744826d684efa513cbffa97/src/emc/nml_intf/canon_position.cc#L73 >> >> (as well as !=) >> >> I don't know the best way to go about debugging this. Do you know how I >> could find where the zero length moves are being added to the trajectory >> planner and what normally prevents that from happening? >> >> Yours and Schooner's insights have been helpful so far. Maybe we can work >> together to figure out what is going on. >> >> -John >> >> On Saturday, February 25, 2017 at 1:16:32 PM UTC-7, Robert Ellenberg >> wrote: >>> >>> Hi All, >>> >>> My guess is that this is a mismatch between canon and the TP in how a >>> zero length segment is defined. I recall running into a similar issue with >>> LinuxCNC. If we're lucky, it's been fixed already in another branch and >>> it's a matter of porting the fix over to Machinekit. I'll take a look this >>> weekend. >>> >>> Best, >>> Rob >>> >>> On Sat, Feb 25, 2017 at 10:08 AM schoo...@btinternet.com < >>> schoo...@btinternet.com> wrote: >>> >>>> >>>> On 25/02/17 11:47, schoo...@btinternet.com wrote: >>>> >>>> >>>> On 25/02/17 07:55, icecube45 wrote: >>>> >>>> It's seemingly a different line each time I run the file, this time it >>>> was line 20462, which is either the middle of >>>> >>>>> G1 X-9.794 Y-69.769 A29.4549 >>>>> >>>>> G1 X-10.971 Y-71.809 A29.5489 >>>>> >>>>> G1 X-13.951 Y-71.809 A29.6678 >>>>> >>>>> or the middle of >>>> >>>>> >>>> >>>> G1 X31.776 Y-64.609 A48.9986 >>>> >>>> G1 X34.755 Y-64.609 A49.1175 >>>> >>>> G1 X35.933 Y-62.569 A49.2115 >>>> >>>> >>>> defendant on if comments count as lines or not.. >>>> Nothing seems out of the ordinary here, which is why I'm so confused. >>>> >>>> >>>> The error is defined as TP_ERR_ZERO_LENGTH >>>> >>>> https://github.com/machinekit/machinekit/blob/master/src/emc/tp/tp_types.h#L61 >>>> >>>> The trajectory planner is dark magic with which I have no particular >>>> familiarity. >>>> It was certainly not developed to squirt plastic in tens of thousands >>>> of extremely small moves. >>>> >>>> My only guess might be that depending upon what blending settings you >>>> have, it may not recognise a commanded move(s) as >>>> any sort of move at all. >>>> But I could be completely wrong. >>>> >>>> Hopefully Robert or someone with more knowledge will chime in. >>>> >>>> >>>> Just to flesh this out a bit >>>> >>>> This is the code which is throwing the error >>>> >>>> https://github.com/machinekit/machinekit/blob/master/src/emc/tp/tp.c#L1937 >>>> >>>> if (tc.target < TP_POS_EPSILON) { >>>> rtapi_print_msg(RTAPI_MSG_DBG,"failed to create line id %d, >>>> zero-length segment\n",tp->nextId); >>>> return TP_ERR_ZERO_LENGTH; >>>> } >>>> >>>> If you switched on debugging, you should see this message in >>>> /var/log/linuxcnc.log >>>> >>>> This is why I am surmising that an extremely small move, with some >>>> rounding down from the tp settings, >>>> could be causing the error. >>>> >>>> TP_POS_EPSILON is defined here >>>> >>>> https://github.com/machinekit/machinekit/blob/master/src/emc/tp/tp_types.h#L44 >>>> as 1e-12 ( which is 10 to -12 or 0.000 000 000 001 !! ) >>>> >>>> Why this is occurring I don't know, but you can switch on debugging and >>>> confirm that this is indeed the bit causing it. >>>> >>>> You can also switch off blending (G64 P0) or adjust the blend tolerance >>>> settings ( G64 Pn.nn ) and see if it improves. >>>> >>>> >>>> >>>> >>>> On Friday, February 24, 2017 at 4:47:47 AM UTC-8, Schooner wrote: >>>>> >>>>> >>>>> On 24/02/17 12:03, icecube45 wrote: >>>>> >>>>> Does anyone have any idea what this error code is? It occasionally >>>>> happens, yet I can't isolate what is actually causing it, nor what the -7 >>>>> error code actually means. >>>>> >>>>> >>>>> >>>>> https://github.com/machinekit/machinekit/blob/master/src/emc/motion/command.c#L953 >>>>> >>>>> It means that it does not like one of the parameters to a linear move. >>>>> >>>>> EMCMOT_COMMAND_BAD_EXEC means there was an error trying to initiate >>>>> the command. >>>>> This would suggest the command was valid syntax but the acc, vel, move >>>>> extent or some other factor was not. >>>>> >>>>> Unless you can tell us what the move asked for was, it is impossible >>>>> to guess. >>>>> >>>>> line xxxx should be a number, it may not strictly equate to the line >>>>> number but should be a number non the less. >>>>> >>>>> >>>>> >>>>> I'd appreciate any advice on how to fix this error - it's popping up >>>>> randomly and stopping my prints. >>>>> >>>>> For reference, I'm on a BeBoPr++ lineardelta configuration. >>>>> -- >>>>> website: http://www.machinekit.io blog: http://blog.machinekit.io >>>>> github: https://github.com/machinekit >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Machinekit" group. >>>>> To unsubscribe from this group and stop receiving emails from it, send >>>>> an email to machinekit+...@googlegroups.com. >>>>> Visit this group at https://groups.google.com/group/machinekit. >>>>> For more options, visit https://groups.google.com/d/optout. >>>>> >>>>> >>>>> -- >>>> website: http://www.machinekit.io blog: http://blog.machinekit.io >>>> github: https://github.com/machinekit >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "Machinekit" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to machinekit+...@googlegroups.com. >>>> Visit this group at https://groups.google.com/group/machinekit. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>>> >>>> -- >>>> website: http://www.machinekit.io blog: http://blog.machinekit.io >>>> github: https://github.com/machinekit >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "Machinekit" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to machinekit+...@googlegroups.com. >>>> Visit this group at https://groups.google.com/group/machinekit. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>>> >>>> -- >>>> website: http://www.machinekit.io blog: http://blog.machinekit.io >>>> github: https://github.com/machinekit >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "Machinekit" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to machinekit+...@googlegroups.com. >>>> Visit this group at https://groups.google.com/group/machinekit. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >> website: http://www.machinekit.io blog: http://blog.machinekit.io >> github: https://github.com/machinekit >> --- >> You received this message because you are subscribed to the Google Groups >> "Machinekit" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to machinekit+...@googlegroups.com <javascript:>. >> Visit this group at https://groups.google.com/group/machinekit. >> For more options, visit https://groups.google.com/d/optout. >> > -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. 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