Re: [CAD_CAM_EDM_DRO] Re: Best source for Servo's ??

Hi Ron,

As long as you are careful to eliminate noise (screened cables, proper
earthing etc), accumulated error should be zero.

The positioning accuracy depends on your gearing. The Z axis of my mill
is geared for .000125" per step which IMHO is a bit coarse. As a test I
moved it down onto a 0.001" dial gauge and zeroed both it and the dial
gauge. I then moved the Z up and down a bit and returned it to zero. I
repeated this a few times and the dial gauge read exactly zero every time.

When moving a servo is always behind the commanded position while
accelerating or ahead while decelerating. I have no way of measuring the
error but I doubt if it is more than .001" at low speed. While
accelerating hard near rapid speed (somewhere around 200IPM if I run
Mach2 flat out) the error is a lot more than that, possibly as high as
.012". The drives will fault if the error exceeds .016" (128 steps)

In practise I have turned Mach2 down to about 100IPM. 200 is bad for my
heart!

Les



R Rogers wrote:

>Hi Les, what kind of tolerance on positioning will they hold? if its within a thou. and will repeat without accumulated positioning errors that would be good enough.
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>Ron
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