Wiring sample of the C94 board connection with Huanyang VFD
The initial installer configured UCCNC or Mach3/4 to control the spindle, you only need to set the max spindle speed and set the jumpers on the C94 to control the relay logic (FOR/REV or ON/OFF and CW/CCW).
Before wiring to the VFD, use a multimeter to verify that you do get a 0-10vdc proportional to the commanded speed and that the relays are clicking as expected when you command the spindle.
After wiring, make sure to configure the VFD to take the control signals from the terminals.
The configuration you did on the initial Step by Step instructions for Mach3 or Mach4 configured the control software and plugin, you just need to set the max spindle speed.
Keep in mind that you need to configure the VFD to take the control signals through the terminals:
Run from Terminal.
Take Reference Speed from Terminal
Run the spindle at different speeds and test with a DMM that you are getting a 0-10vdc from the analog output terminals that is proportional to the commanded speed. The Relays should also activate to start the spindle in the commanded direction. This will confirm that your configuration is OK.