I have a 15M control and the manual talks about using G84.2 and G84.3 to rigid tap. I know that my machine needs a spindle encoder to do this, how do I tell if my machine is equipped with one? I tried just calling up a G84.2 using the example in the manual but I got a "Invalid G code" alarm, does this mean it can't do it, or that maybe the subroutine is missing?