To control the VFD via the PWM signal coming off your CNC Controller, you'll need to ensure there are two settings configured correctly.

If your CNC Controller outputs a 0-10v PWM signal, then you'll need to configure P2013=0 (default) and P2015=10 (also default).

However if your CNC Controller outputs 0-5v PWM signal, then you'll need P2015=5. 

The PWM/GND signal is accepted by our vfd via the VF1 and GND pins behind the VFD's cover.

As you can tell P2015 controls the upper voltage limit of the incoming PWM signal... while P2013 controls the lower voltage limit.

On occasion a CNC controller continuously sends out a very low voltage resulting in your spindle running a few hundred to a thousand rpms even when the controller says it's zero.
A simple way to compensate for this issue is to adjust P2013=0.4  This means if the voltage over PWM is anything less than  0.4v, then the spindle will be set to 0rpms.