CAD CAM EDM DRO - Yahoo Group Archive

Re: A lot

Posted by Jon Elson
on 1999-09-06 22:48:13 UTC
"Arne Chr. Jorgensen" wrote:

> So, let me just ask what you think of this:
>
> You have the jog function, and there must be variables to it in the
> shared memory space. What if you had switches that enabled the
> handwheel signal - as jog commands. That should be clean and easy
> enough. Would that satisfy your needs ?

yes, this is what I had in mind, anyway. Except, the handwheel would not
work very well for jogging. I want to be able to twiddle down to the
.0001" level, but handling every encoder tick as a separate jog event
would be way too slow. So, you really need to run this through logic
that is already present in the motion control stuff, namely, "electronic
gearing", where the machine is moved some distance that is a ratio
of the handwheel movement. The lathe threading function works this
way, so the motion software already has this feature.

>
> Here is some setups:
>
> Stg board - you use digital io for the switches, and a spare
> encoder counter.

Only problem here is that the STG card has very limited digital I/O
that isn't already allocated to limit and home switches. I think keyboard
functions (which can also be provided by an extra keyboard encoder
and a keyboard 'tee' box) could be used to select the handwheel jog
mode and axis.

> If I understood some of the things Fred said, - then I take it that
> he would be willing to include options for a handwheel, but he
> wanted to know how the users would like it, and how it should
> function. ( Hit me hard if I am wrong, Fred )

Well, the simplest I can think of, is a keyboard key (like the jog mode
and incremental step size) to select the axis and jog by handwheel mode,
and a spare encoder channel (maybe a parameter in the .ini file selects
what channel #). If somebody wants to get fancy, there are little boards
you can get that scan a key matrix and send keyboard signals. there are
also boxes you can buy that will multiplex 2 keyboards, sending key codes
from whichever keyboard has keys struck. This could make a very simple
pendant control.

Jon

Discussion Thread

Arne Chr. Jorgensen 1999-09-06 11:10:44 UTC A lot Jon Elson 1999-09-06 22:48:13 UTC Re: A lot