Re: PWM vs Constant current and G-rex

The G-Rex will be a little bit more than just that.

1) Run 6 independent axis or, run 3 independent X,Y axis or, run 2
independent X,Y,Z axis or, etc. Mix and match.

2) Constant contouring 2D, 3D thru 6D.

3) Roll your own CNC software. Anyone with Notepad and a USB port can
operate it.:-) The communication is ASCII text string. Send:

x123y456z789<cr>

The X,Y,Z axis move in true 3D to the X=123, Y=456 and Z=789
coordinates. As soon as motion starts, the G-Rex replies with:

xyz<cr>

This means the last XYZ motion is executing, send data for the next
XYZ coordinates. Send more data and it constant contours. Don't send
any, it comes to a stop. Send more and it picks up from where it left
off.

Or, send a megabyte text file containing 100,000 concatenated line
segments; 2D, 3D, or even 6D. The G-Rex will give you a constant
contoured path for those 100,000 vector segments automatically. Make
it 10-million if you like and have the time. It can handle 800 XYZ
line-segment coordinates per second.

How fast? The first named axis' programmed velocity is the constant
contour velocity. It and aceleration is set by sending:

Vx1234<cr> or Vy12<cr> or etc.
Ax567<cr>

Send x123y789<cr> and the CC speed will be Vx (Vx = 1234)
Send y789x123<cr> and the CC speed will be Vy. Both take XY to the
same coordinates.

A lot more stuff as well; this is just a little of the motion stuff.

Mariss

P.S. Running steppers PID closed-loop improves them a little. How
about zero to 3,000 RPM in 180 degrees (1/2 rev)? One revolution
start to stop in 0.04 seconds.






--- In CAD_CAM_EDM_DRO@yahoogroups.com, R Rogers <rogersmach@y...>
wrote:

>
> /// A stepper motor with an encoder is essentially an AC servo with

very poor high speed torque. For the same price as a servo. This
quest for the unstallable stepper escapes me totally. Seems if the
stepper is in an application that is causing it to malfunction then
it would need to be replaced by a more reliable servo system. ///

>
>

>
>
> //// With Mach3, The pulse rate frequency can be set as high as

45k/sec. This is ample for any system unless someone is wanting to
use some ridiculous amount of encoder count resolution that no mill
or router table could take advantage of. ///

>