I'm trying to dial in my spindle control but the most voltage I can get out of My controller is 3.13v. Is that correct?
Your thread title states "Blackbox x32 pwm" The PWM port is a 3.3v logic signal yes (See docs:blackbox-x32:layout [OpenBuilds Documentation] section 2 for details) PWM is a pulse train, not an analog voltage, you need an oscilloscope to see the pulse widths. (just high/low pulses of different lengths) Spindle, assuming its a VFD, you should be using the 0-10v port not the PWM port... docs:blackbox-x32:connect-vfd [OpenBuilds Documentation] Any incorrect wiring can damage either of these outputs, be very mindful while doing wiring to prevent damage to the controller. Wiring a 0-10v input to a PWM output for example, can cause problems, double check documentation before making connections