Novusun NVCM Motion Controller Enable PWM

Hi There

I've been stuck for couple days trying to figure out how to use the PWM of the NVCM motion controller

the manual is located below and written very poorly

https://www.nvcnc.net/pdf/NVCNC_NVCM_EN.pdf

it states in the manual product specification section : "1 port 0-10V spindle speed analog output interface(can change to PWM output)"

I am able to control the analog output by connecting to the VSO pin of the controller but how do I change the analog output to PWM

I am using an oscilloscope to monitor the output signal

any one here knows the solution