Zero Backoff occasionally not working

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  • March 27, 2013 at 2:10 am #3957
    mabel
    Member

    When homing with the x-axis, it occasionally does not do the movement for Zero Backoff.  It backs off the latch until it opens and then goes on to homing the y-axis without moving the zero backoff distance.  I went through the homing sequence 20 times, and 3 of those times it did not do the Zero Backoff.  I am going to continue to test it and try to get it working, but I wanted to know if you had any ideas as well.  Below is a copy of the x-axis settings.

    Thank you!

     

    [xam] x axis mode                 1 [standard]

    [xvm] x velocity maximum         50.000 mm/min

    [xfr] x feedrate maximum        600.000 mm/min

    [xtm] x travel maximum          150.000 mm

    [xjm] x jerk maximum       20000000 mm/min^3

    [xjh] x jerk homing        20000000 mm/min^3

    [xjd] x junction deviation        0.0500 mm (larger is faster)

    [xsn] x switch min                3 [0=off,1=homing,2=limit,3=limit+homing]

    [xsx] x switch max                2 [0=off,1=homing,2=limit,3=limit+homing]

    [xsv] x search velocity         150.000 mm/min

    [xlv] x latch velocity          150.000 mm/min

    [xlb] x latch backoff             5.000 mm

    [xzb] x zero backoff              5.000 mm

    April 2, 2013 at 5:01 pm #3979
    Riley
    Keymaster

    Can you post the results of a $$ command and also hit reset and give us the build / version number info.

     

    Thanks,

     

    Riley

    April 10, 2013 at 12:08 am #3985
    mabel
    Member

    Here are the results of a $$ command.  It gave the build and version number first as build 370.08 and version 0.95.

    [fb]  firmware build            370.08
    [fv]  firmware version            0.95
    [hv]  hardware version            7.00
    [id]  TinyG ID                    9H3906-SQE
    [ja]  junction acceleration  100000 mm
    [ct]  chordal tolerance           0.010 mm
    [st]  switch type                 0 [0=NO,1=NC]
    [ej]  enable json mode            0 [0=text,1=JSON]
    [jv]  json verbosity              4 [0=silent,1=footer,2=messages,3=configs,4=linenum,5=verbose]
    [tv]  text verbosity              1 [0=silent,1=verbose]
    [qv]  queue report verbosity      0 [0=off,1=filtered,2=verbose]
    [sv]  status report verbosity     2 [0=off,1=filtered,2=verbose]
    [si]  status interval           100 ms
    [ic]  ignore CR or LF on RX       0 [0=off,1=CR,2=LF]
    [ec]  expand LF to CRLF on TX     0 [0=off,1=on]
    [ee]  enable echo                 0 [0=off,1=on]
    [ex]  enable xon xoff             1 [0=off,1=on]
    [baud] USB baud rate              5 [1=9600,2=19200,3=38400,4=57600,5=115200,6=230400]
    [gpl] default gcode plane         0 [0=G17,1=G18,2=G19]
    [gun] default gcode units mode    1 [0=G20,1=G21]
    [gco] default gcode coord system  1 [1-6 (G54-G59)]
    [gpa] default gcode path control  2 [0=G61,1=G61.1,2=G64]
    [gdi] default gcode distance mode 0 [0=G90,1=G91]
    [1ma] m1 map to axis              0 [0=X,1=Y,2=Z…]
    [1sa] m1 step angle               1.800 deg
    [1tr] m1 travel per revolution   20.290 mm
    [1mi] m1 microsteps               8 [1,2,4,8]
    [1po] m1 polarity                 1 [0=normal,1=reverse]
    [1pm] m1 power management         1 [0=off,1=on]
    [2ma] m2 map to axis              1 [0=X,1=Y,2=Z…]
    [2sa] m2 step angle               1.800 deg
    [2tr] m2 travel per revolution   20.290 mm
    [2mi] m2 microsteps               8 [1,2,4,8]
    [2po] m2 polarity                 1 [0=normal,1=reverse]
    [2pm] m2 power management         1 [0=off,1=on]
    [3ma] m3 map to axis              2 [0=X,1=Y,2=Z…]
    [3sa] m3 step angle               7.500 deg
    [3tr] m3 travel per revolution    0.044 mm
    [3mi] m3 microsteps               8 [1,2,4,8]
    [3po] m3 polarity                 1 [0=normal,1=reverse]
    [3pm] m3 power management         1 [0=off,1=on]
    [4ma] m4 map to axis              3 [0=X,1=Y,2=Z…]
    [4sa] m4 step angle               1.800 deg
    [4tr] m4 travel per revolution  360.000 mm
    [4mi] m4 microsteps               8 [1,2,4,8]
    [4po] m4 polarity                 0 [0=normal,1=reverse]
    [4pm] m4 power management         1 [0=off,1=on]
    [xam] x axis mode                 1 [standard]
    [xvm] x velocity maximum         50.000 mm/min
    [xfr] x feedrate maximum        600.000 mm/min
    [xtm] x travel maximum          150.000 mm
    [xjm] x jerk maximum       20000000 mm/min^3
    [xjh] x jerk homing        20000000 mm/min^3
    [xjd] x junction deviation        0.0500 mm (larger is faster)
    [xsn] x switch min                3 [0=off,1=homing,2=limit,3=limit+homing]
    [xsx] x switch max                2 [0=off,1=homing,2=limit,3=limit+homing]
    [xsv] x search velocity         150.000 mm/min
    [xlv] x latch velocity          150.000 mm/min
    [xlb] x latch backoff             5.000 mm
    [xzb] x zero backoff              5.000 mm
    [yam] y axis mode                 1 [standard]
    [yvm] y velocity maximum        200.000 mm/min
    [yfr] y feedrate maximum        600.000 mm/min
    [ytm] y travel maximum          150.000 mm
    [yjm] y jerk maximum       20000000 mm/min^3
    [yjh] y jerk homing        20000000 mm/min^3
    [yjd] y junction deviation        0.0500 mm (larger is faster)
    [ysn] y switch min                3 [0=off,1=homing,2=limit,3=limit+homing]
    [ysx] y switch max                2 [0=off,1=homing,2=limit,3=limit+homing]
    [ysv] y search velocity          50.000 mm/min
    [ylv] y latch velocity           50.000 mm/min
    [ylb] y latch backoff             5.000 mm
    [yzb] y zero backoff             10.000 mm
    [zam] z axis mode                 1 [standard]
    [zvm] z velocity maximum         40.000 mm/min
    [zfr] z feedrate maximum        500.000 mm/min
    [ztm] z travel maximum           75.000 mm
    [zjm] z jerk maximum         200000 mm/min^3
    [zjh] z jerk homing          200000 mm/min^3
    [zjd] z junction deviation        0.0500 mm (larger is faster)
    [zsn] z switch min                3 [0=off,1=homing,2=limit,3=limit+homing]
    [zsx] z switch max                2 [0=off,1=homing,2=limit,3=limit+homing]
    [zsv] z search velocity          40.000 mm/min
    [zlv] z latch velocity           40.000 mm/min
    [zlb] z latch backoff             2.000 mm
    [zzb] z zero backoff              3.000 mm
    [aam] a axis mode                 1 [standard]
    [avm] a velocity maximum       3600.000 deg/min
    [afr] a feedrate maximum       3600.000 deg/min
    [atm] a travel maximum           -1.000 deg
    [ajm] a jerk maximum       20000000 deg/min^3
    [ajh] a jerk homing        20000000 mm/min^3
    [ajd] a junction deviation        0.0500 deg (larger is faster)
    [ara] a radius value              1.0000 deg
    [asn] a switch min                0 [0=off,1=homing,2=limit,3=limit+homing]
    [asx] a switch max                0 [0=off,1=homing,2=limit,3=limit+homing]
    [asv] a search velocity         600.000 deg/min
    [alv] a latch velocity          100.000 deg/min
    [alb] a latch backoff            10.000 deg
    [azb] a zero backoff              2.000 deg
    [bam] b axis mode                 0 [disabled]
    [bvm] b velocity maximum       3600.000 deg/min
    [bfr] b feedrate maximum       3600.000 deg/min
    [btm] b travel maximum           -1.000 deg
    [bjm] b jerk maximum       20000000 deg/min^3
    [bjd] b junction deviation        0.0500 deg (larger is faster)
    [bra] b radius value              1.0000 deg
    [cam] c axis mode                 0 [disabled]
    [cvm] c velocity maximum       3600.000 deg/min
    [cfr] c feedrate maximum       3600.000 deg/min
    [ctm] c travel maximum           -1.000 deg
    [cjm] c jerk maximum       20000000 deg/min^3
    [cjd] c junction deviation        0.0500 deg (larger is faster)
    [cra] c radius value              1.0000 deg
    [p1frq] pwm frequency             0.000 Hz
    [p1csl] pwm cw speed lo           0.000 RPM
    [p1csh] pwm cw speed hi           0.000 RPM
    [p1cpl] pwm cw phase lo           0.000 [0..1]
    [p1cph] pwm cw phase hi           0.000 [0..1]
    [p1wsl] pwm ccw speed lo          0.000 RPM
    [p1wsh] pwm ccw speed hi          0.000 RPM
    [p1wpl] pwm ccw phase lo          0.000 [0..1]
    [p1wph] pwm ccw phase hi          0.000 [0..1]
    [p1pof] pwm phase off             0.000 [0..1]
    [g54x] g54 x offset               0.000 mm
    [g54y] g54 y offset               0.000 mm
    [g54z] g54 z offset               0.000 mm
    [g54a] g54 a offset               0.000 deg
    [g54b] g54 b offset               0.000 deg
    [g54c] g54 c offset               0.000 deg
    [g55x] g55 x offset              75.000 mm
    [g55y] g55 y offset              75.000 mm
    [g55z] g55 z offset               0.000 mm
    [g55a] g55 a offset               0.000 deg
    [g55b] g55 b offset               0.000 deg
    [g55c] g55 c offset               0.000 deg
    [g56x] g56 x offset               0.000 mm
    [g56y] g56 y offset               0.000 mm
    [g56z] g56 z offset               0.000 mm
    [g56a] g56 a offset               0.000 deg
    [g56b] g56 b offset               0.000 deg
    [g56c] g56 c offset               0.000 deg
    [g57x] g57 x offset               0.000 mm
    [g57y] g57 y offset               0.000 mm
    [g57z] g57 z offset               0.000 mm
    [g57a] g57 a offset               0.000 deg
    [g57b] g57 b offset               0.000 deg
    [g57c] g57 c offset               0.000 deg
    [g58x] g58 x offset               0.000 mm
    [g58y] g58 y offset               0.000 mm
    [g58z] g58 z offset               0.000 mm
    [g58a] g58 a offset               0.000 deg
    [g58b] g58 b offset               0.000 deg
    [g58c] g58 c offset               0.000 deg
    [g59x] g59 x offset               0.000 mm
    [g59y] g59 y offset               0.000 mm
    [g59z] g59 z offset               0.000 mm
    [g59a] g59 a offset               0.000 deg
    [g59b] g59 b offset               0.000 deg
    [g59c] g59 c offset               0.000 deg
    [g92x] g92 x offset               0.000 mm
    [g92y] g92 y offset               0.000 mm
    [g92z] g92 z offset               0.000 mm
    [g92a] g92 a offset               0.000 deg
    [g92b] g92 b offset               0.000 deg
    [g92c] g92 c offset               0.000 deg
    [g28x] g28 x location             0.000 mm
    [g28y] g28 y location             0.000 mm
    [g28z] g28 z location             0.000 mm
    [g28a] g28 a location             0.000 deg
    [g28b] g28 b location             0.000 deg
    [g28c] g28 c location             0.000 deg
    [g30x] g30 x location             0.000 mm
    [g30y] g30 y location             0.000 mm
    [g30z] g30 z location             0.000 mm
    [g30a] g30 a location             0.000 deg
    [g30b] g30 b location             0.000 deg
    [g30c] g30 c location             0.000 deg

    April 10, 2013 at 8:57 am #3992
    alden
    Member

    I have a suspicion of what’s going on here. I suspect that the latch operation takes the switch to a point where it’s right on the edge of firing. Then the backoff fires the switch again and ends the backoff. I think it’s worth an experiment to lock out switch detection during the backoff and see if that doesn;t prevent this. I’ll add it to my list, or you can hack the code in cycle_homing.c if you want to experiment yourself.

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