ACU-RITE CNC 3500i - Manual (Page 238)

212 7 Programming: Canned Cycles, sub-programs
7.
3 Pr
obing Cy
cles
 You must have the tool positioned over the probe stylus so the tooth
that sticks down the furthest is directly over the center of the probe
stylus and above the stylus less than 0.100" (2.0 mm).
To measure the tool length:
 Jog the tool to the top of the probe stylus so that the tooth that
sticks down the furthest is directly over the center of the probe
stylus.
 From the Manual Data Input Mode with G-code MDI selected, type
G152 Tn Dd and touch the Start button. Where T is the tool number
and D is roughly the diameter of the special tool. For example, G152
T3 D3.5.
 The spindle turns on in reverse and the Z-axis should go down and
touch the top of the probe stylus keeping the X and Y position the
same, then rapid up 0.02" (0.508 mm) and then retouch using the
slow feedrate programmed in the machine setup parameter. The
cycle then updates the tool-length offset register clearing any value
in the length wear register, turn the spindle off and return the tool
to the Z height where it started.
 The Tool Length has been set and you can now change to another
tool, and repeat steps 1 through 3.
Large tools can result in probe damage if the touch
feedrate is set too fast. For this reason, the cycle
parameters: M, S, and R have been added to enable the
programmer/operator to override the values in the
machine setup parameters for the specific tool being
checked or set.
If the spindle is locked, you may have to unlock it to
manually orient the tool tooth over the probe stylus.