On Sat, Jan 21, 2017, at 04:28 AM, John Morris wrote:


> I also thought of these three possible intended scenarios pointed out in 
> this thread, and can think of valid arguments for each, briefly:
> 
> 1. The manual says it's an error, and it's up to the user to avoid it 
> (status quo)
> 2. The controller detects the condition, and informs the user
> 3. The controller detects the condition, and compensates by adjusting 
> spindle speed

#3 is impossible for machines where spindle speed is not controlled by LCNC.
For example my lathe has only M3/M5.  Single phase motor controlled by
contactor, with manually changed belts to the spindle.

#2 is possible during actual program execution - can't do G33 without a
spindle encoder, and if you have an encoder, you have spindle speed
feedback and can decide if the speed is OK.

But #2 may not be possible during generation of the preview.  During 
preview the spindle is not running.  The only thing LCNC can do is assume
that the spindle speed will be whatever the most recent S-word specified.
But on a machine like mine, the S-word doesn't actually control anything.
IF the programmer is disciplined enough, he can use the S-word to tell
LCNC how fast he intends to run the spindle.  But LCNC can't rely on that
being the actual spindle speed.


-- 
  John Kasunich
  [email protected]

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