Is it possible to calibrate spindle in manual mode?
-Set  S(rpm)
-Measure voltage at the output of the converter then the PWM to 0-10V
-RPM value  =Output voltage * 40Hz(For spindel  24000rpm max) * 60
-Wrote down the value in the table. Click Next Measure.

It can accurately calibrate the output voltage is controlled by the spindle speed.

Сan be such already in mach3?

Best regards, Sergey