On Mach3 main screen there is at the bottom right the spindle speed screen. I can't find any explanation in the manual of what the inputs on this screen mean.

Is the RPM where I input my speed?
What S ov means?
What SRO% means?
I guess the "Spindle Speed" is what Mach3 thinks what my RPM is?

RPM is the actual RPM the spindle is doing and will be there if you have an index pulse set up.

Speed is the commanded spindle speed
S-OV is the overridden speed of the spindle in relation to the commanded speed.
SRO% Is the percentage of override you have for the spindle.

Hood

Thank you Hood, good to know