Re: [CAD_CAM_EDM_DRO] Poor Man's Servo System

I have now tested DESKNCRT with my DRO board installed and stepper
motors with encoders. I'm impressed. It works just like a servo system
except thousands of $$ less. I used deskncrt with a 126 oz inch dual shaft
stepper that was modified by adding a modified HP encoder on the back end. I
used an encoder that had the same count as the stepper however it did not
make any difference in that in quadrature the encoder is 4X the counts.
After configuring deskncrt. I turned the stepper motor with the power to the
drivers off. It worked like a DRO. I could turn the motor shaft either
direction and go positive or negative. The display in deskncrt read the
movement. With power to the drivers turn on, I used a pair of pliers to
force the stepper from the starting point. Just like a servo system the
drivers forced the shaft back to the starting point when the pliers were
released. It worked that way in either direction.
Then I ran a G code file called seahorse.tap several times.
Each time causing the motor to lose position by holding the shaft with
pliers. If the induced error was less than the ferror setting in the INI
file it would recover and always returned to the starting location at the
end of the file. If the induced error was greater than the ferror setting
the program would cease.
While I don't have it set up on a machine yet it looks like a diamond in the
rough. The GUI needs some work but WOW it seemed to over come stepper motor
resonance problems generally noted on stepper motors running without a load.
If there are other DESKNCRT users out there I would like some email
with your comments.
Dan