Anyone good at math ?

[VictorH]

yes the encoder will be stationary but the wheel will roll as the head moves up and down   sorta like when you get you truck stuck ;) the wheels are turning but nothing is moving

I believe what you describe is called a "string pot"

[sandsawmill14]

i think  kensfarm is talking about a string pot but what I was talking about is simply an encoder with a wheel on it

[Brad_bb]

I get the same as Dan too.  Guess I'm really late here.  Didn't read all the replies before doing the math.
I tend to look at the problem as ratios.
600 pulses is to 1 revolution as 1000 pulses is to x , which is written as
600/1=1000/x
solving for x
x=1000/600 = 1.667

Now you know how many revolutions equals 1000  pulses

So now if you want to know the size of the wheel that will give you 12 inches in 1.667 revolutions, you write it as
1.667(2*Pi*r)= 12 inches
Note: 2*Pi*r is the circumference of the wheel, where r is the radius and Pi is 3.1415
Solving this equation for r
r=12/(1.667*2*3.1415) = 1.146 inches
multiplying by 2,  the diameter of the wheel equals 2.291 inches, and a circumference of 7.200 inches.

[ozarkgem]

I will use a vertical stationary chain and the encoder will move up and down with the head. A sprocket on the encoder will be used to turn the encoder. No chance of wheel slippage.  Are you spring loading the wheel so it will stay in constant contact?

[Kbeitz]

I will use a vertical stationary chain and the encoder will move up and down with the head. A sprocket on the encoder will be used to turn the encoder. No chance of wheel slippage.  Are you spring loading the wheel so it will stay in constant contact?

Spring loaded mounted at the top away from everything.

[Kbeitz]

I took some time thinking and playing with the scaling.
I think I'm going to set it up for reading 1/4" This would
make reading it so much easier. The scaling for that came
to .800. Bow if I want 1" I just run it to 4. 2" = 8 and so on.