I got my CNC setup. I am able to control all the four stepper Nema 23 motors using NVUM board interfaced with mach3 cnc board. I also have a setup for a spindle, which is connected to VFD. I am manually controlling my VFD. There is no connection between NVUM usb board and VFD. The problem is when I try to run them together. As soon as I press my run button on vfd, the spindle starts working but my mach 3 shows that the device is not connected and all the control to my stepper motor is lost. But if I do not run my spindle through vfd, all the stepper motors works fine with mach 3. I invested so much time but got no solution. Please help.