Re: stepper-servo system

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Thomas J Powderly
<tomp-tag@...> wrote:

>
> Ballendo , Graham,
>
> yes ,Ben Fleming's book has a LM339 op-amp that outputs a drive

signal to a small motor or an amp.

> The schematics are pim to pin wiring diagrams so I can't recognize

the circuit right away.

> But it will run an analog servo, not a stepper.
> Neither will the circuit I posted.
> But Ben has a new model generator, maybe he has a new circuit.
>
> TomP
>

Ben's circuit is quite simple it is a fixed feedrate and relies on
the right motor/gearbox/screw selection, of course this bodes well for me.

I have already converted Flemming based unit to stepper control but I
am using like a fixed speed DC motor system as the pulse train comes
from a 555 timer.

As far as I know only the generator is changing but I could be wrong.

The real sinker EDM I have used has a true DC servo system with gain
and feed settings etc, I want my stepper system to emulate this more
closely rather than just bang-bang window control but I'll start with
that.

I set up an area for development last night, laptop, propeller, LCD
TV, oscilloscope. It just needs a coffee machine! Most of the night
was spent wrestling with wireless network wizards, they make you life
easier you know, yeah right!

Graham