Re: [CAD_CAM_EDM_DRO] How to establish repeatable home position w/steppers?

hi guys,
To keep the text from getting too long I'm starting over. Doesn't mean the ideas were not good

In the words of the Troll..... "years ago"... I did a control (stepper) for a spectophotometer. ie. separates out colors of light.
e.g prism, grating, etc.
Used a A/D off the photomultiplier. Indexed by finding the peak of the beta deuterium line. (maybe 485 nm: been too long to
remember) Then to test the repeatibility went searching for the peak of the Cu line at 224.7 nm. With a resolution of 50 steps/nm.
it never missed. i.e as long as steppers are not too loaded to move they are very reliable. This system used drivers directly
driven by a bit pattern from the parallel interface of the computer. (PDP-11)...for you young guys the instruction set is much like
the Mot 68xxx series.

Along the same lines one could actually use a gage block to stall the steppers and call this zero. :-)

Dave