On Sunday 03 April 2016 09:37:05 Mark wrote: > I understand that, but that doesn't really answer the question - what > determines the machine/controller resolution/precision, the machine > and electronics notwithstanding. If I set the G Code coordinates to > x.x is the resolution/accuracy actually 0.1" or is it 0.01" or 0.001" > or something greater? > > Lets say the machine is at X 0.0 and Y 0.0. The G Code commands a > move to X 1.0 Y 0.0 (again in inches). Does the machine move to that > new position with a precision of 0.1", 0.01", 0.001" or something > greater (using the theoretically perfect machine of course)? > > Does it make a difference if the G Code coordinates have one, two, > three or more digits to the right of the decimal point? > > Mark > > On 04/03/2016 09:06 AM, John Thornton wrote: > > http://linuxcnc.org/docs/2.7/html/gcode/overview.html#_number > > > > JT > > > > On 4/3/2016 7:48 AM, Mark wrote: > >> Friend of mine and I have had an email discussion going over the > >> last few days about movement precision, accuracy and resolution. > >> > >> Lets say there are three different G Code files, A, B and C. > >> > >> In file A, the coordinates are such: X x.x Y x.x > >> > >> In file B, the coordinates are such: X x.xx Y x.xx > >> > >> In file C, the coordinates are such: X x.xxx Y x.xxx > >> > >> For simplicity's sake, no Z axis and the units are inches. > >> > >> Using file A for example, with the coordinates only given with 0.1" > >> precision, what exactly does the controller do? Does it actually > >> work to 0.1" precision or does it work to moreprecision, vis-a-vis > >> when making moves? > >> > >> Is file C, with precision to three decimal places the standard > >> precision in controllers, or do we just use three decimal places in > >> the G Code because it's good enough for gummint workand the > >> controller can actually make more precise moves (dependent of > >> course on the machine, the mechanics and the electronics)? > >> > >> Mark
As others have said, the missing precision in the command is filled with zero's, clear down the the micro-step needed (for steppers anyway) to get X to 1.10000000. In servo setups I'd assume the deadband is at least the backlash else it will hunt. So that in a servo setup, would probably be the major part of the actual positioning error. How close it gets to that is up to the machines mechanical variables. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785471&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
