Re: More HANDWHEEL

As I think Fred said earlier, messing with the encoders and in hardware switching back and forth between a hand wheel encoder
and the axis encoder is likely to cause some glitches and the accuracy is lost. You really do not want to have to "go home"
after you jogged to a position. You must trust the location display at all times.

An option might be to add a tiny amount of electronics to the hand wheel and send the signals through the serial port using DTR
CD or some other lines. Even if some pulses are lost, it is not critical since we just keep cranking until the display reads
the desired position.

Let's not forget that hardware today is almost free. An extra printer port is less than $20, sometimes less than $10. If the
extra hardware keeps a system "clean" and makes life easier for the programmer, by all means use it.
Bertho Boman
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> From: "Arne Chr. Jorgensen" <instel@...>
> -------> snip
> There is a number of ways to do this, and I guess you could store
> your new position as an offset. Maybe use something like the
> backlash function. I think a lot depend on the actual machine and
> the way you make your programs. I don't know how this would be on a
> lathe, or on mill. Maybe you should try to define how you think it
> could be implemented on each kind of machine. You could also have a
> "user" home, or say that the machine will home in to the position
> where you changed reference, then swap back with a predefined feed
> rate. You could also have several display output, current and
> actual. On the actual machine, it worked as a charm. It was a
> plasma cutter, - so no need for tool changes. This had current and
> actual position displayed. In a program this would change to
> current and next or commanded value - as far as I recall.

----------> snip