Sergio got it.
The new Ezgo controls coming out soon will have a new J4 pug for the FN control.
Handyman, to answer your question.
With the FNKS you have to set your ranges in each profile beforehand. (that's 3 profiles, normal and 1 and 2) Once those are set you can limit/increase your rpm within those ranges and if you want a different range you just change profiles. To set the actual range, you have to lengthen/shorten your little slider bar, if you hover your mouse over the ends you’ll get the double sided arrow which lets you extend/limit your ranges. If you want to only adjust one of the sliders with your knob instead of all three you just set your min/max to the same number (wherever you want it all the time) and it won’t have the ability to move but the other sliders will.
I hope this clarifies. Please let me know if you have any questions.