Re: [CAD_CAM_EDM_DRO] Re: Encoder resolution

Jon Elson <elson@...> wrote:
R Rogers wrote:

>Jon,
>
>I see, so one allowable error is based on machine acceleration/speed exponentially. And another monitors the axis at rest/hold. How does EMC handle this discrepancy? Does it fault the software or does it correct it self on the next ramp down?
>
>

Well, both numbers are at work all the time, although the scaled limit
scales down to zero at rest,
leaving the fixed minimum value as the only operative number. If the
following error is exceeded,
all motion is commanded to a stop at maximum deceleration, and you get
an error message
on the screen. So, at present, it doesn't have "feedrate compensation",
where the system is
slowed down, just like a manual feedrate override, when it gets into
trouble. That could possibly
be added.

I'm not sure what you mean by "correcting itself at the next ramp
down".

/// I thought it may when decelerating and the axis is capable of being corrected (because acceleration/stall caused the discrepancy) it might resynchronize the pulse train with the encoder data and continue on. /// Thanks, Ron



The G-code program
would be interrupted, and all axes would get back in coordinated motion
when the program is
restarted. It is about the same as hitting the emergency stop button.

This all only applies to a closed-loop servo system where the computer
is reading encoder position
and calculating servo values in real time for the motor drives.

Jon



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