Re: counting encoder holes ? BEST encoder range ?

The Gecko 340 and Rutex 990H drives both have multipliers so that you
won't be limited to your 1650 RPM...Not sure what reduction you are
using.

-Brady

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
<dave_mucha@y...> wrote:

>
>
> > 3. Your servo driver ~ 2 issues ~ 1. a PID multiplier will
> > effectively reduce the number of pulses that the software needs

to

> > output. IE- if you use a 4X mult. you would only have to output
> about
> > 11,000 steps max from software to go the same as the max 45,000
> > listed earlier (using Mach2 as and example) 2. If running a high
> > count encoder & Gecko, you may have issues with error counts
> because
> > they are so small. In other words, depending on reduction etc, a
> few
> > encoder count errors may only total .00001" mechanical
> error...that's
> > just too small. You'll pull your hair out! The Rutex has a much
> > higher error count...but if used with low count encoders, can

cause

> > the servo to hit an axis extent before it stops on it's own.
> >
> > Hope that helps...as said, I'm no expert...
> >
> > -Brady
>
>
> your third point is interesting and pretty much where my attention

is

> focused.
>
> if one has a motor that has a 2,000 step encoder, it would be

similar

> to a stepper with a 200 step and a 10x microstepper driver.
>
> The encoder resides on the motor, so it is seperate from machine

axes

> and more on motor postioning.
>
> A motor with 2,000 steps would move 0.18 degrees per 'step' from

the

> driver.
>
> I'm not as concerned about postioning as it is for a plasma cutter
> and the final accuracy is not that important.
>
> But, the motor speed would be limited to pulse count of the

software.

> at 2,000 steps, it would limit the motor to 45,000 hz (for Mach2)

or

> 22.5 rev's / second or 1,650 RPM for the motor.
>
> Starting with a treadmill motor of 5,100 RPM at 110 V, the power
> supply limit of about 66 volts (48-1.2*1.414) is 60% of motor

design

> or 3,068 RPM at the max voltage of the motor.
>
> Then limiting that to 1,650 due to encoder limitations means the

max

> speed for the motor is roughly 32% of nameplate.
>
> Seems that the compromises abound when trying to piece-meal parts
> from surplus.
>
> But, not have any experiance with servo's, I'm not sure just how
> awful it would be.
>
> Dave