Hi
i have a problem with my 4kw VFD with is a 4kw 18000rpm spindle
i can fine get the spindel to 18000 rpm and 300hz
but if i set the mach3 to 9000 rpm the the vfd is showing 174.5hz and not 150hz
and i have measured the pwm signal to 5v

now i have use two days and i cant find the error

/kenneth