We are coming close to starting a retrofit on a VMC.  We drill and tap several holes and want to rigid tap on this machine.  We have used floating tap holders with great success in the past, but we purchased new equipment that has rigid tapping and now we're spoiled, so much faster and better on our tools. 
The HiCON Integra says it can Rigid Tap.  I am going to put a 2000 count encoder on the spindle for true RPM.  What do I need to do/have to implement this?

The HiCON Integra 7766 has one differential encoder input next to the relay and DAC I/O where the spindle connects. There is also a single ended encoder input located on the board near the MPG port.   

Yes.  I've got an encoder hooked up to the Differential encoder on a lathe here in the shop.  It gives us a true RPM and works very well. 
But for the mill, I'm asking how to implement the rigid tapping.  How do I get the Z and the Spindle to sync.

The rigid tapping feature requires an activation code to be purchased in order to use it. The feature can be activated using the VSI device manager. If you provide us with email address we can send PDF manual on using HiCON rigid tap in Mach4.

Have you ever used a Tapmatic style auto-reversing tapper?  It is actually faster than rigid tapping on smaller threads and less wear and tear on the machine than rigid tapping because of the very small mass that reverses.  Ours reverses out at twice the speed going in. It would be interesting to see how much power is consumed bringing the motor and spindle mass to a full stop and then accelerating up to full speed again. Versus a couple of clutches reversing.

I've seen the tapmatic pretty cool and very fast.
  But implementing it on our ATCs will be no fun.   

HARSH.MPF
N10   G90 G71 G94 F200 ;
N20   T03 D01 M06 ;
N30   S1000  M03 ;
N40   M08 ;
N50   G00 X25 Y10 Z10 ;
N60   CYCLE84 ( 10 ,  0 , 2 , -25 , _ ,_ , 3 , 5 , _ , 90 , 200 , 500 , 3 , _ ,_ ,_ ,_ ,_ )
N70   G00 X25 Y35 ;
N80   CYCLE84 ( 10 ,  0 , 2 , -25 , _ ,_ , 3 , 5 , _ , 90 , 200 , 500 , 3 , _ ,_ ,_ ,_ ,_ )
N90   M05 M09 M30 ;
 
more info - http://www.hdknowledge.com/2018/09/how-i-learn-program-with-sinumerik-cycle-84-rigid-tapping-cycle.html

HARSH.MPF
N10   G90 G71 G94 F200 ;
N20   T03 D01 M06 ;
N30   S1000  M03 ;
N40   M08 ;
N50   G00 X25 Y10 Z10 ;
N60   CYCLE84 ( 10 ,  0 , 2 , -25 , _ ,_ , 3 , 5 , _ , 90 , 200 , 500 , 3 , _ ,_ ,_ ,_ ,_ )
N70   G00 X25 Y35 ;
N80   CYCLE84 ( 10 ,  0 , 2 , -25 , _ ,_ , 3 , 5 , _ , 90 , 200 , 500 , 3 , _ ,_ ,_ ,_ ,_ )
N90   M05 M09 M30 ;
 
more info - http://www.hdknowledge.com/2018/09/how-i-learn-program-with-sinumerik-cycle-84-rigid-tapping-cycle.html

I don't think the command CYCLE84... would be recognized by Mach3 

Tweakie.