Hitachi P1 VFD Installation And Manual page 15

Calibrate RPM Feedback
If your VFD is enabled as a Mach spindle (and there can only be one enabled at a time), follow the
procedure below.
You will need to scale your emulated RPM feedback in the Mach software. Calculate your feedback
ratio as follows:
Max Spindle RPM / 3600 = Feedback Ratio
Then while the control is disabled follow the next few steps:
Step 1: Click on Configure -> Control at top of the Mach screen. Then select the "Spindle" tab
shown in Figure 7.