Re: Servos and Vexta

Hi Jon,

Yes, looks like quite a bit of change from my slow little Sherline! I
think I'll start out with only about 40V, until I get things checked
out.

Didn't find a 1P/2P switch, my labels only say CS and CCW, so I guess
I'll work that out on my own.

Alan KM6VV

Jon Elson wrote:

>
> Alan Marconett KM6VV wrote:
>
> > I'll take your advise on the servos, 2:1. Sounds like good reasoning!
> > I certainly don't need/want to go that fast!
>
> One of the problems with servos (doesn't happen all that often if you
> build things right) is that a servo runaway WILL go as fast as the
> motor/power supply combination CAN go, and that can be pretty
> scary. I rarely run my machine over 60 IPM, I'm just not in that
> much of a hurry, and if you do it manually, you are likely to have a crash.
> When I get a program really working just right, I may turn the feed rates
> up a bit.
>
> Since I have only manual tool changes, and sometimes I touch the tools
> to the top of the part, and sometimes I rig the program to use length
> offsets for different tools, I can get confused, and forget to reset the Z
> axis when a tool change requires it. Nothing like plunging a drill bit
> into a block of aluminum at 60 IPM to raise your heart rate!
>
> Ahh, but CNC is so nice! I was able to turn the part over (it was designed
> to have blind holes exactly opposing each other) and drill extra deep from
> the other side, and hit the broken drill bit dead on. It dulled my drill, but
> I was then able to drive the broken bit out of the hole and resharpen
> the unbroken bit. Saved the part!
>
> > The Super Vexta (I just found out) also has a half/full step switch, and
> > I can see a hint at the drive being able to do step/dir as well as
> > CW/CCW reading between the Japanese "lines". Possibly if the CCW line
> > is held high?
>
> Mine has a 2P / 1P switch that does this, I think. The terminal labels are
> "pulse" and "CCW/CW", which gave me a pretty strong indication that
> those were really "step" and "dir".
>
> > I can't make it out in diagrams accompanying the Japanese
> > text. I didn't find any other switches. There is a T.I.M. signal, and
> > an H.off signal out of it, and some diagrams relating them to steps, but
> > I've yet to determine their use. One signal would seem to be "tied" to
> > "step 0" and every 10 step thereafter. I probably don't need them!
> > 1000 spr will be nice!
>
> Some other labels I've figured out is "AWO" = all windings off
> and "timing" is an output that becomes active at only one full step
> polarity. I guess this is used like the encoder index signal to refine
> home position.
>
> Jon
>
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