The new code is based on reading of your rpm. What are the specs on your tach? I am going to guess that it is
-+ some percent +- 1 RPM.... I believe that the turn diagnostics real time is more accurate than your tach ( from
some tests we did as check / and you don't have the specialty equipment to do it).
Now the DRO, may say 500, stay there or go back and forth some, say 500,501,500....... Even if the DRO stays at say 500, that dosn't mean your rpm isn't changing, it does, maybe small, but it does. Now you will see those changes in the rotation speed real time box.
BTW, don't forget that what is being measured is via the index pulse sensor. A sensor can be triggering slightly differently even if the signal is conditioned. I will leave that kiind of stuff to the electronics folks.
So the rpm that will be applied to the threading cycle will be the appplication end rpm. You will see that after the first pass that it is a different rpm, since during the first pass Mach used rpm info from it to plan the next pass and adjusts the feedrate accordingly. Now small but very important.
SO you have a real time rpm which is varing and an application end rpm used for the actual threading.
By the way i suggest spindle speed averaging in config.
Now as far as your negative display....maybe someone else can chime in and explain.
RICH
BTW,what is important is the way your motor, belt/ gearing, the index pulse act as a "system" so don't get hung up on some finite element of them because , again extremely difficult to measure and even if you can, you probably may have not have a way of improving it .
Forgot to mention that i am still at version .030.