Well, I finally got my spindle tach installed and sending Mach3 speeds throughout my spindle range, nice!  My setup:

Seig 7x14
Gecko 540
UC100
Mach3

Silly me, I thought that when I got that done that Mach would automatically increase/decrease voltage to the motor to get the actual to match the requested speed.  My setup doesn't. 

I have a couple of questions now that I have an accurate spindle speed but I will post each in its own message.

First one, is it just my spindle board or is that the way Mach3 is designed to work, ask for a speed and then you can observe what your machine actually spins at and you request/ adjust to get what you really desire?  If it is supposed to auto adjust what spindle/other boards do you use or recommend?

TIA

RT