What make/model of BOB do you have?
If using a separate power supply then you will likely need to tie its 0V to a 0V on your breakout so that the signal is being referenced at the same potential .
4mm may be ok, try and see, you will soon know as when you spin fast you will not get an accurate reading if it is too small
Hood

ive no idea, ill phone angel tech later and double check with him, unless he replies here first.

all wired up i think?

just not sure on how to set up ports and pins.

i believe im connected to input 12. so i activated input 12.

but im getting no reading still

You set the Index input to the port and pin number you have it connected to.
Hood

hood, is this a slow sensor or something?

got a 11mm wide slot and the highest rpm reading i can get is 1340

my machine goes up to 4000rpm

cheers

Have you remembered to set Index Debounce to Zero?
The sensor is plenty fast so shouldnt be an issue with that, the BOB may be a problem, could have slow optos on it?
Hood

the sensor is connected straight to the db25 connector, not to the BOB

debounce is at 0

Shouldnt be a problem then, can you attach your xml and I will take a look to see if there is an issue in it.
Hood

errr sure but ive not got a clue what your talking about lol

what file and where do i find it?

also i keep snapping taps, im using this code

m3 s1000

g00 x20 y0
g00 z3

G95
G1 Z-10 F0.5
G1 Z5
G94

m5
m30

The xml is in the main Mach3 folder and will have the name of the profile you are using followed by a xml file extension. You will need to copy it to your desktop then rename to attach to the forum, call it andy_con.xml and that should work.

You need to have a short rapid retract for that tapper, if I recall correctly, to engage the reverse clutch quickly.
Hood