Re: 4th Axis Concept (long)

--- In CAD_CAM_EDM_DRO@y..., Chris L <datac@l...> wrote:

> Sheez, if this is this basic why is no one marketing such a little

beast? You know

> what they get for a small powered Indexer.......

Talking of small powered indexers, I have a working prototype of a
small powered indexer, based on a PIC microcontroller and a bipolar
drive (L297/298), intended to drive a rotary table or dividing head
fitted with a 400 half-steps per rev stepper motor. Brief features
list (at present):

- 2-line by 16-character LCD display and 16-key membrane keypad;
- Setup parameters stored in Non Volatile RAM - remembers the
settings from last time it was powered on;
- Will cater for any worm/drive ratio between 1:1 and 99:1;
- Adjustable initial/max feedrates and jog rates, from dead slow to
around 60 degrees/s with a 72:1 worm drive (e.g., the Sherline rotary
table);
- Adjustable ramp rate;
- Software-based backlash compensation;
- Bipolar chopper drive - usual L298 spec (2 amps/phase), with
chopping current settable via software;
- "Jog Mode" gives CW/CCW jog in increments of 1/100th, 1/10th, 1 and
10 degrees, with display of desired and actual angular position to 3
decimal places (where the desired position cannot be achieved, actual
position is within 1/2 step of the desired position);
- "Division Mode" allows operator to set the number of divisions
between 1 and 999. Table can be driven CW and CCW one division at a
time - display shows current division number, plus actual angular
position in range 0 - 359.999 degrees;
- "E-Stop" key halts any move immediately, but the current/desired
angular position is remembered - hence, position is not lost on E
Stop.
- "Degrees Mode" - similar to Division Mode, but the move is
specified in degrees to 3 DP;
- Motor connector is plug-compatible with Taig's CNC equipment (6-pin
DIN plug);
- Breakout connector provides for external control of CW/CCW moves
and E-Stop, and also provides step/direction outputs if needed to
control a higher power driver stage.

I'm currently working on getting the board into production - watch
this space.

Regards,
Tony