search

gnea / grbl

An open source, embedded, high performance g-code-parser and CNC milling controller written in optimized C that will run on a straight Arduino
https://github.com/gnea/grbl/wiki
Other
4.04k stars 1.6k forks source link

error 33 with large I or J values (?) #574

Open Cdriko opened 5 years ago

Cdriko commented 5 years ago

hello I use gcodetools derivative in inkscape to generate gocodes. Sudently, using dot lines, it generates a lot of G3 paths with very large radius instead of just lines. The result is like that : `;(...) G0 X33.9176 Y243.2292

M03 G1 F3500.000000 S255 G03 X36.2921 Y243.2228 I237.1478 J52084.2875 F3500.000000 S255 G1 F3500.000000 S255 G03 X39.0374 Y243.2154 I-24.9066 J98219.9788 M05

G0 X39.6771 Y243.2126

M03 G1 F3500.000000 S255 G1 X44.7973 Y243.1988 M05

G0 X45.4372 Y243.1959

M03 G1 F3500.000000 S255 G02 X48.1825 Y243.1886 I2604.9744 J-485351.2826 G1 F3500.000000 S255 G03 X50.5575 Y243.1824 I41.402 J17696.8596 M05 ;(...)`

But at each G02 or G03, I've got an error 33. Maybe it's because the large values for I and J ???

how fixing that ?

chamnit commented 5 years ago

At those large radii and short target distances, a straight line is about the same. Unfortunately this is a limitation of 32-bit floating point math. I suppose Grbl could look for edge cases like this one and insert a short line for you but there is limited flash left to insert code like this.

Cdriko commented 5 years ago

thanks. So I've made a python loop to truncate the long floats. at the begining, ti seems to work but at the line 1626, I've the same error after this line :

`

G1 F3500.000000 S255 G02 X56.6168 Y325.5949 I-97892. J-102606 G1 F3500.000000 S255 G02 X56.443 Y324.8939 I-49900. J64662.5`

Maybe even the than values are shorten than 7 numbers, the result of the interpolation overflow a stack ?

swarfer commented 5 years ago

you should rather convert those G02 to G01 like this G1 F3500.000000 S255 G01 X56.6168 Y325.5949 G01 X56.443 Y324.8939

notice that the actual distance moved is very short, 0.72mm and you are not going to see the difference between an arc and a straight line.

even better is to tell your Gcode generator to do this for you, ie, generate lines (G01) for any segment shorter than 1mm and radius larger than, say, 5000mm