Re: [CAD_CAM_EDM_DRO] encoder indexing pulse

Carey,

OK, then as long as there was only a single index signal while the
optical switch was "active", then I think you could just "LOGICAL AND"
the two "active" signals, and route the output of the gate to the
parallel printer interface. Two "active HI" (4.5v) signals would "AND"
together in for example a 7408 is a quad, two input positive AND gate,
two HI's in give a HI out. a 7400 is a quad, two input positive NAND
gate, two HI's in give a LOW (.5v) out. Depends what level you are
looking for. 7004's are hex inverters. Use to get HI's to LOW's. Many
more gates and families of gates are readily available. 74LS and 74HC
families are popular.

Alan

"Carey L. Culpepper" wrote:

>
> Alan: Actually the first optical switch would be mounted somewhere on
> the table and it would be tripped- then the index signal would be close
> behind. When both are tripped I would then have a completed circuit for
> a signal. The first switch "and" the index. The optical coming into play
> only at one point in the travel of the machine table. Does that make
> more sense? Carey
>