I'm running GRBL 1.1 on an Arduino Uno, which is connected to a HY VFD as follows: GRBL Spindle PWM > VFD VI GRBL Ground > VFD ACM VFD DCM > VFD FOR The 1.5kw spindle works fine when I control it from the control panel, but when I switched PD001 = 1 on the VFD (allows external control) and use GRBL, I run in to problems. The spindle powers up to the minimum allowed rpm as soon as I turn the VFD on. I can control the spindle speed via GRBL, but "powering off" (i.e. PWM = 0) still means that the spindle spins at the minimum rpm I've set. Can anyone suggest where I can start troubleshooting this please, as it's unusable in the current state. For reference, my VFD is configured as follows: Code: PD005 =400 PD004 =400 PD003 =400 PD072 =400 PD144 = 3000 PD001 = 1 PD002 = 1 PD006= 2.5 PD007=1.2 PD008=220 PD009=15 PD010=8 PD011 = 120 PD070 = 1 PD73 = 120 PD141 = 220 PD142 = 7 PD143 = 2 GRBL is configured with $30 set to 24000 and $31 set to 0.