Re: MAX-VELOCITY global = bad

This is a question that would be better answered by Fred, but here is my
understanding of it.

In EMC MAX_VELOCITY is not considered the velocity of a single axis, but the
velocity of the cartisian move along the tool path. By way of example, if
you were to give the following move assuming we are at X0 Y0 to start:
G01 X5 F10
the velocity would be 10 ipm at 0 deg as the combined cartisian movement is
along a single path.
Now if we give the move
G01 X5 Y5 F10
The velocity would be 10 ipm at 45 deg (the combined cartisian movement ),
but when looked at on the X axis the velocity would be closer to 5 ipm (no I
am not going to do the math to figure it out exactly, just trying to get the
idea across) and the same thing on the Y axis.

Now if we were to make the moves G00 instead with a MAX_VELOCITY of 10 ipm
everything works out the same in example 1, but in example 2 there are 2
possibilities. If MAX_VELOCITY is considered as a global value along the
combine path as EMC does your tool bit will move along the 45 deg path at 10
ipm. But, if you are looking at the MAX_VELOCITY as restricting the axis
only in the 0 and 180 deg movement to that set value your tool bit will now
be traveling closer to 20 ipm as both X and Y axis are moving at the full 10
ipm.

Is this the right way to implement it?? I don't know, but it is based upon
the fact that EMC looks at the coordinated movement and not at each axis
individually.

Tim
[Denver, CO]