I forget the specifics, but the Mach 3 software will throw an error code if it does not see the controller. On first guess the software starts in E-stop mode and that has to be reset.
Also the Mach 3 has to be properly configured for the Omio. Simplest to use the version downloaded from WCP or Omio.
We are setting up our new Omio too and we are trying to find the OMIO stepper motor and ball screw specs so we can determine the travel count per inch. Can anyone help with this?