Re: [CAD_CAM_EDM_DRO] Re: Servo Motor Hookup with Gecko's (question to Jon)

caudlet wrote:

>Jon, could you clear up some confusion I have about your board? It
>appears to interface to a PC parallel port and outputs step and
>direction pulse to a motor driver.
>
>

Yes. (It can also put out full-step phase signals, if that's what you
need.)

>I talks about monitoring the encoders. Does it form a local feedback
>loop and keep stepping until the step count matches?
>

No, it produces a pulse RATE as specified by the computer. The COMPUTER
keeps it moving
at some rate until it gets to where it is supposed to be. This is just
like a servo system, the
CNC control specifies the rate, evaluates the error by looking at
position, and sends adjustments
to the velocity to minimize the error.

> What happens if
>the input from the PC and the encoder feedback get too far out of
>sync?
>
>

They are ALWAYS out of sync by some small amount. This is the following
error. EMC
(the only software that currently supports this board) monitors the
following error, and commands
an e-stop if the error exceeds the limit soecified in the setup file.

>Will standard parallel port programs like MACH1 drive it? (Does it
>take standard parallel port S&D signals)
>
>

No, it takes velocity (rate) commands, and responds with position.
Drivers only exist for
EMC at present. My web pages specify the entire interface, but since it
emulates a servo
system, not a step-direction system, most programs are not built around
that model.

Jon