Support probably walked you though this, but just in case…
When you initially set up the machine, on the first run of Carbide Motion did you answer the spindle question “VFD Spindle” and make sure that BitRunner is off. Because that will influence whether the spindle control pin (green wire) is on/off (0 volts off, 5 volts on) or 5 volts pulse width modulated (PWM) - which is what the VFD expects to be able to vary its speed. If it is set to on/off, the spindle will be either all on (=24000) or off.
You can look on the “Settings” tab in CM, and look at the “Debug” tab to check. Scroll down that list of settings and look for the “Spindle type” line. It should be set to “1”. Here’s the relevant part of mine.
Machine: Shapeoko 5 Pro
GRBL Version: 1.1h
Carbide Motion 618
Machine Controller State: INIT
Grbl Cycle: Idle
{
“bitRunnerEnabled”: false, ------------------ BitRunner is not enabled
“bitSetterEnabled”: true,
“bitSetterX”: -1.5,
“bitSetterY”: -604.5,
“bitZeroType”: 2,
“connection”: 5,
“lastConfigSent”: 0,
“lastProbeIndex”: 0,
“lastSizeOption”: 1,
“odometer”: [
{
“cleared”: false,
“minutes”: 1828.625483333333,
“startDate”: “2023-07-25”,
“travelX”: 2472024.808167219,
“travelY”: 1250756.1670565903,
“travelZ”: 364846.7115054559
}
],
“showCarbideRouterRpm”: true,
“spindleType”: 1, ------------------------------ This line is the other one you’re looking for.
“travelX”: -1237.0,
“travelY”: -623.0,
“travelZ”: -155.0,
“version”: 0, …
You can always re-initialize as a new machine if necessary.