Re: [CAD_CAM_EDM_DRO] Re: EMC Have a Distance-to-go position DRO

ballendo wrote:

>Jon,
>
>I'm surprised you're not familiar with DTG uses. Primarily it is
>useful when first running a new program. If you "think" it's headed
>where it shouldn't, you can feedhold, change to DTG readout, and see
>if you're gonna have a bad thing happen. Looking through the code you
>can do this by subtraction, but if you have a computer right there,
>why are you doing math in your head<G>
>
>

Well, I only used the A-B control for about 6 months. It broke down
4 times in that span, and had plenty of other problems, notably mediocre
servo performance at a 100 Hz servo update rate. Also, I had to go through
a lot of trouble to dripfeed programs to it from a PC to the paper tape
reader port.

I rarely have a problem with this since using EMC and the little programs
I have written for simple operations (rectangular pocket, circular
pocket, etc.)
as they are pretty reliable.

>Another use is in setting tool offsets, when they are in relation to
>a "master" tool. The master tool is set as zero, and all other tools
>can be set using the DTG value.
>
>

Hmm, this is interesting. I made a presetting fixture that is used with a
surface plate and a height gauge to create the tool length table. It worked
very well.

>Sometimes DTG is used when a program is interrupted. Just a sometimes
>useful way of looking at there you're at, in relation to where you're
>going. Same as having a trip mileage in your car telling you how far
>you've come, a road signs telling you how far left to go...
>
>

Most moves are so short it just isn't a big deal for me. I can see in some
huge gantry bed mill with a 50 foot axis that there could be cutting
moves that
take hours.

Jon