Setting up Soft Limits
Note: You should have Version 1.423.5 or newer to perform this properly.
1) Home the machine
2) zero all axes
3) carefully jog the machine to the opposite ends of travel on all axes. Remove the tool from the spindle and get the Z axis as low as possible.
4) Click Setup, then Options
5) Check the box marked "use soft limits"
6) Click the box "Use current pos". This will fill in values for M1, M2, M3 and M4 if present.
7) Click OK in the lower left.
Your machine will now stop short of the end of travel just before it hits the switch (unless your axis is set to rotary in setup, system).
Your system will not jog faster than 200IPM until it has been homed.