I was doing some research and found this on another forum, does it sound right?

To calculate RPM use this formula, in which you will have to find RPM's when you have Hz.
1 RPM = 0.01666666667 Hz
Formula: 0.01666666667 × RPM = Hz
On our VFD if you select the >> button about 3-4 times, it will change from Hz, A, or ROTT.
When the LED's are lit on Power, FOR, and ROTT, you should be able to see the RPM the spindle is running at, our maximum setting for these spindles is 400Hz / 24000 RPM.

I also found a post saying there is an order that you need to set the programs in the vfd? I cannot get desk cnc to allow me to change rpm's but it will allow me to change rpm through the perimeter on the vfd. I assumed it was DeskCNC being antiquated but maybe it's a setting I've got wrong, any advise?
Thanks