Re: Quadrature?

A good example is a bridgeport series 2 which has 10 tpi screws and a
2:1 belt reduction. With a standard 500 line encoder you get 2000
pulses per rev, times 2, times ten. 40,000 counts per inch. This
works out to one quarter of a "tenth" or 25 millionths. .000025" per
count. (at 50 inches per minute feedrate = 30Khz pulse frequency)

the example below gives 40 millionths (4 tenths of a tenth)

In my experience anything smaller than 5 tenths (.0005") will never
show up on 99 percent of the machines we are likely to encounter.
Past the 3rd decimal place the numbers really start to float.
Measuring below the 4th decimal (in inches) is tricky and expensive.

end of 4a.m. rant.
Joe V.

<snip>
If an encoder, say a rotary encoder, has a count per

> > revolution of 2500, and I have a pitch on a screw that is say 10

tpi. Then

> > its possible to have a dro with .00001"? (one hundred thousanth

of an

> > inch)