Re: [CAD_CAM_EDM_DRO] Re: digital to analog

carlcnc@... wrote:

> Look in the archives for Xynetics Plotter
> After talking with the guys at Applied Motion Products I discovered
> that this unit has linear bi-polar steppers!
> The hitch is that [believe it or not] the motors are driven by 150V
> 8a .Originally designed and hooked to HP 3000 ,I have everything but
> the computer,
> Now it gets beyond me: drivers accept analog input via a d/a
> converter card!that was installed in the computer[that I don't have]
>
> Actually ,I asked the same question, why would any engineer put
> analog between two digital devices?
> They did,in 1987 when this unit was built.
> I could run the motors with Geckos but thought it would be worth
> trying to use the 150V drives as is.

OK, now I know what these things are. What this is is an X-Y
plotboard, or chart recorder, as used by NASA to
plot the position of a rocket after liftoff from radar data, and often
to also plot a computer generated predicted impact point if thrust
quit right now. They had these things in the launch control centers
for the range safety officer, as well as the rest of the people to monitor
the launch. The reason for the high power is that they often had
2 pens, plotting a string of dots in 2 colors for the two different
tracks. The pen would have to go and put a dot at 2 different
spots every second.

There are plenty of 2-channel D/A converters available from all
sorts of outfits that sell computer-related stuff. You need to find
out what the voltage range of the analog input is. The problem is
that it probably uses linear pots for position feedback, and they
are not all that accurate, so the whole unit won't be terribly
accurate.

Jon