mesa 7i76e vfd spindle speed problem

Raban wrote:

On the motor i have a 48 teeth pulley and 34 on the spindle.
The 200 ppr encoder is on the motor 1:1
(200ppr x 4 )/48 x 34 = 566,666667

In that case you will not be able to use the index on the encoder for rigid tapping. (Well, technically, it might actually work, but you won't be able to peck-tap, ie run the cycle twice in the same hole)

But any sensor that you can set up as a 1ppr index on the actual spindle can be used to drive the Mesa encoder index channel. 
 

Raban wrote:

Wait a moment the encoder is channel A , channel B and channel I ( index connected to the encoder index input in the TB4 mesa 7i76e card)

To further elaborate..

For a _lathe_ you absolutely need the index to happen exactly once per spindle revolution to allow single-point threading to work. 

But, having checked with the mailing list, you can rigid-tap on a mill with an index that is not synchronised to the spindle, just as long as the spindle encoder scaling takes in to consideration the gear ratio _and_ as long as you never try to do more than one rigid-tapping operation in the same hole.