I am having trouble getting the C11 BOB, Huanyang 2.2kw inverter and spindle to communicate with Mach 3 screen (RPM). I can turn the spindle on and off and can control the speed with the inverter but it will not display the rpm of the spindle in mach. If you touch the + or - buttons for spindle speed in Mach it will display rpm for a brief moment ( the length of time the button is depressed) Can anyone help?