How does a DRO work

[dberndt]

Ok, I'm curious as to how a DRO works. I've never used one and I'm wondering how the principle works. I assume that they dont just work with an encoder on the table screws like a cnc system or anything like that?

I'm interested in what the general principle of operation is, how it mounts, and any links for any sort of a home made option/circuit design.

[ESjaavik]

Originally Posted by dberndt Ok, I'm curious as to how a DRO works. I've never used one and I'm wondering how the principle works. I assume that they dont just work with an encoder on the table screws like a cnc system or anything like that?

Not exactly, but similar. The encoder is not a disk but stretched out to become a linear encoder. There are different other systems based on magnetic or capacitive principles too.

For info on glass scale linear encoders check out the Heidenhain web pages.

[Al_The_Man]

There are a few sites for the home builder using a cheap PC for display, some that show how to convert the relatively cheaper rotary encoder to linear like this http://www.lindsayengraving.com/othe...rests/dro.html
There is also one out there that uses a cheaper linear scale reflective design. If I come across it I will post it here.
Al

[Al_The_Man]

This site http://www.metalworking.com/has also usefull projects for the DIY'er machinist, it includes a method of DRO using a caliper as a measuring device.
Al

[Ken_Shea]

Thanks for the interesting link Al, and the engraving was a special treat.