Re: [CAD_CAM_EDM_DRO] Stepper Motor steps and other questions

Hi Russ,

Yes, the Gecko's can be connected (Step/dir) directly to a parallel
port, and driven by a "controller" program. 28V should work reliably,
although 40 or 50V (up to 80V) would be useful. Recall that the G201's
are microstepping, and will require 10x your required steps/sec, Easily
achieved. G210's have a multiplier board that allows the driver to work
at 10x, 5x, 2x and 1x rates of microstep, instead of just the 10x.

Your parallel port (4 bits needed for two motors) is your interface.
The controller software runs in an intensive loop to generate the
required steps to move the axis.

Another thought, if you want to offload this calc, is to use a pair of
CY525 stepper driver IC's,

http://www.controlchips.com/

Either parallel or serial "commands" are sent to the chips, and they
generate the requested step/dir pulses, complete with
acceleration/deceleration.

Otherwise, for the straight software approach, I'd suggest you
"register" and get Dave's TurboCNC (Pascal) code, and use it as a guide
to generating step/dir with a parallel port. Other programs are also
available with their source code.

One thing you might want to add to your interface is a pair of "home"
switches, so that you can zero the axis (relate the motor position to
the plotter board).

HTH

Alan KM6VV


Russ Revels wrote:

>
> Thanks to Alan, Mike and Jan.
>
> I just got back in town and had to catch up on the emails. I will be
> removing all of the gearing, latitude and longitude motors and gears and
> also the integrators. The main object of the modification is to make the
> things simple to maintain. I guess a stepper motor and controller is about
> as simple as you can get. As far as speed is concerned the fastest I need
> for movement in one axis would be (worst case) a ship speed of about 35kts
> due north. I m guessing that would come out to be about 5 ipm. I get that
> from approxmate numbers:
>
> 60 mph = 88ft/s
> 30 mph=44ft/s =14yds/s
> 14yds/s * 60sec = 840 yds/min
> 200yds/in max scale of bug.
> (840yds/min)/(200yds/in)= 4.2 ipm at 30 mph.
> 10tpi leadscrew with 200 step/rev
> 2000 steps/in
>
> I will have a switch to tell the computer whether to calculate at 2000
> yds/in. (normal) or 200yds/in. (high definition).
>
> Since I need about 35 mph I guess about 5ipm as an absolute maximum speed.
> I hope I'm not too far out in left field with this.
>
> Do I understand correctly that the Gecko 201 that I see mentioned takes the
> output from the computer and generates the pulses to the motor to make it
> move the required steps? If I run a 28vdc supply to the motor thru the
> Gecko how much more circuitry would I need to make this run reliably? I
> anticipate putting 200+ oz-in motors on the leadscrews. Since I don't
> require position feedback information do I need any other stuff to make this
> work? I understand that the software would have to calculate the
> positioning information and generate the correct steps. It does that now
> with the stepping motors, just at a different rate. Is there a PCI
> interface card available to drive the gecko driver?
>
> Thanks again,
>
> Russ N4FT
>
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