Re: Basic stepper control question

Hi Kevin

I've read through this thread, and I noticed that you use Dan Mauch's
5 amp boards. I am cnc'ing a mill, and have 3 of his 5 amp boards
done, have 3 of his motors, and I'm almost ready to do a computer
control test of motor motion. The last thing for me will be to hook
up the hardware to a mill. I want to learn the full system first,
including how to use 3d cad.

But, I was curious how you like the Camtronics kit, and how reliable
and durable it is. Also, I am curious if (and how) you use the half-
stepping, and if this a good feature. I plan to use Art Fenerty's
Master5 software to run the whole show.

I have not yet hooked up my db25 junction board to the computer, or
to my 3 driver boards yet, but it seems mostly straight forward. I'm
not too sure about the I/O devices jack on the little junction board,
but I'll learn about it as required.

Sorry if this seems a bit meandering, but I just haven't fully
connected the system yet, so I was curious about various parts of
Dan's system. Any feedback is very much appreciated, especially if
you've come across problems that are not obvious to the average cnc
hobbiest.

Thank you, Tom Kay.



-- In CAD_CAM_EDM_DRO@y..., "Kevin P. Martin" <kpmartin@t...> wrote:

> I would guess that the 50 clicks on a 200-step motor is due to

residual

> magnetism of the field core. The iron has some hysteresis (which

can be a

> significant source of heat at high step rates), so it is unlikely

to have

> *absolutely no* field when all current it off.
> In particular, I would expect it to retain a small amount of the

last

> current-generated field, so you may find that these 50 clicks move

each time you

> run the motor.
>
> There is also the question of what you mean by "kill all the

current" to the

> motors. As an example, when I shut down my Camtronics 5Amp drivers

on my

> sherline mill, first I flip a switch which disables all the motor

drivers (at

> this point the handwheels can be turned freely). Then I turn off

the main power

> switch; invariably I hear the steppers jump a tiny bit. I suspect

that the +5V

> supply is shutting off faster than the +35V motor current supply,

and as a

> result the motors get just a little jolt of current.
>
> So I guess one question is: is the motor current being shut off

just by

> disabling the driver with some sort of control input, or is the

whole power

> supply for the stepper driver being shut down?
> -Kevin