On Fri, Jan 30, 2009 at 02:00:31PM +0100, Robert von Knobloch wrote: > > I notice that the rotary table can be commanded with 'g1 a(xxxx)' to set > it spinning and if I set F300 or F500 then it's rotational speed is > adjusted accordingly (I don't know what F(xxx) means to a rotary table > as it is not linear - can anyone enlighten me?).
Degrees per minute. > If I issue a 'F300' then 'G1 x15 a3600' (Cut a spiral 15mm major radius > and 10 turns) then the rotary table turns at what I estimate as jog speed. > In fact the setting of the F parameter does not seem to influence it at > all when the motion is combined with X,Y or Z movement, although it does > when only rotary motion is programmed. It does, but the units are mm/minute along the X portion of the move. Feeds in units/minute mode (G94) are described here: http://www.linuxcnc.org/docs/html/common_machining_center.html#sub:Feed-Rate You are describing a move of case 1. Your F300 is being taken as mm/minute and for a 15mm move, you are asking it to complete the motion in 15/300 minute = 3 seconds. That is why it looks like jog speed; it's going as fast as it can, trying to complete the move in 3 seconds while obeying the velocity and acceleration constraints given in the ini file configuration. > This seems to me to incorrect operation, but it is also possible that I > have misunderstood something. Can anyone tell me if I am driving the > machine wrongly or is there a bug in EMC/Axis here? When moving axes together that have different units, it's often clearer to use inverse time feed mode (G93). That suggestion is found in the Best Practices section here: http://www.linuxcnc.org/docs/html/gcode_main.html#r3_7 and inverse time mode is documented here: http://www.linuxcnc.org/docs/html/gcode_main.html#sub:G93,-G94:-Set Chris ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
