Hello cnc profs

I have create my own cnc milling machine with the devices in this topic.
this working fine but I wil controlling my HX-WS400 spindle with the PWM from mach3
this is working but my motor is not spinning on full speed about 60%.

does anyone have experions how to controle this?

I have this configuration:
5Axis port 1 PWM > PWM input HX-WS400
GND        >           GND
EN/DIS    >           EN/DIS
P17         >           F/R

when i put in Mach3 MDI input m03 s1200 then my spindle is spinning but not full speed m05 stopts