That should not be an issue at all. You will need to add some code in one of your threads, but I used modbus in Mach3 for my spindle and had a pendant with the override pot and it worked perfect. My pendant for my kmotioncnc machine does not have the spindle or feedrate override pots and I really miss that feature for my bigger machine. I guess I will need to buy a new pendant or add pots to my existing pendant. Modbus sends the commands to the VFD and the override pot would just send another Modbus command to the VFD. You can probably find someone who has already implemented this and has there C code available.