RE: [CAD_CAM_EDM_DRO] Thanks - was: Things to check? is now: RUNNING~!

> -----Original Message-----
> On Thursday 18 September 2003 01:38 am, Tim Goldstein spake:
>
> > High over voltages (like you have) yield hot motors even if the
> > current is set within limits.
>
> No, no... we're down to 75VDC now, thanks to Mr. Variac.
> (...and what a kewl little thing he is, too...)

In the context of limits and motor heating 75 VDC is way up there. What
is the voltage rating of the motors? If is about 3 you are way up on the
curve where the majority of your heating will be due to iron losses
(result of high over voltage). Look at the Gecko whitepaper curves and
you will see that at the upper end of the recommended 10 - 25X
overvoltage range the iron losses go up very steep.

> > So, if you are sure the current is set
> > correctly (you can always reduce it just to try) and you are still
> > getting hot fast then you know it is because you pushed the upper
> > limit on the over voltage.
>
> Well, these are 7.5A motors according to the paperwork, but I might
> just try and drop them down to 6A on the Geckos to see what
> happens. (resistors are cheap)

7.5 amps wired how and how are you wired now? If it was 7.5 amps
unipolar and you are now in a series bipolar you have way too much
current in addition to very high voltage.

> > > Motors *SEEMED* a bit slow for my likes...
> > > Is there a way to speed them up?
> >
> > No. You are already at the voltage limit of the drive. This is
> > assuming that you are not running out of pulse from the
> computer. If
> > you have not yet pushed them to the limit step wise where they are
> > stalling then you may be able to speed them up by feeding them more
> > pulses.
>
> 800Mhz PIII - how do I speed it up? (the pulses)
>

On EMC you have to adjust the various parameters such as period. Then
you can up the max velocity.

> I think this might be where I'm getting confused...
> I'm looking at the G210 guide that came with the Geckos, but only
> see the "full step", "half step", "5u step", & "10u step"
> jumper selections.
>
> Would the "full step" be 1X, and the "10u step" be 10X?
> Is this resolution you speak of related to encoder feedback?
> In other words, if I get the encoders wired up and the DRO board
> in place, will this help with this resolution, or is that
> something different?
>
> And why would multiplying the steps give me poor resoltion?
>
> I'm confused again...
>
> Weyland

Forget the terms as they are confusing and misleading. With a G210 you
have a pulse multiplier. You can set it at 1X meaning for every pulse it
gets from the computer it moves the motor 1 microstep or another way it
takes 2000 computer steps to turn the motors 1 revolution. At the other
end of the scale you have the 10X setting. With this one pulse from the
computer causes the motor to move 10 microsteps yeilding 200 computer
steps per motor revolution. So in 10X step multiplying mode you have
1/10 the resolution as you have in 1X mode. But, it also requires the
computer to put out 10 times the number of steps in 1X mode as in 10X
mode to achive the same movement. Now back to the terms. 10u step is 1 x
mode (one pulse in gives you 1 mocrostep) and full step is 10X mode (one
pulse in moves the motor 10 microsteps).

Using a DRO board will have no effect on the resolution.

Tim
[Denver, CO]
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