Re: [CAD_CAM_EDM_DRO] real tests needed was Re: true closed loop vs. hobby closed loop

ballendo wrote:

>Mariss,
>
>I'm glad you've posted this. Now to get some REAL info we need this
>same test done with a MACHINE attached. Nothing like some added mass
>to affect the numbers...
>
>Because I'm pretty sure everyone here is accelerating more than just
>the motor rotor...
>
>Ballendo
>
>P.S. Even better would be to add your scope to a drive that's
>installed in a BP retrofit, or a large gantry table, and then run the
>drive through some typical toolpaths. Repeat also on smaller
>machines. THEN we'd really know how things stood up for comparison.
>Which would be a good thing, IMO. As you say, nothing like actually
>measuring something. (IN its intended use...)
>
>We could perhaps get Jon E to do the same with his servo amps, and
>then this whole issue would move from the theoretical to the
>practical... (Perhaps someone with rutex's too?)
>
>

I have an old one posted on my web pages, see
http://jelinux.pico-systems.com/servo.html

You can't compare the actual vs. commanded position because the actual
trace covers the commanded. But, obviously, the servo drive is closely
following the trajectory it is supposed to take. This was done at 90 IPM.
This WAS taken from an underpowered servo drive on a Bridgeport
milling machine.

Jon