I have a cnc 4pc c-3 board with a interrupter using a single hole disk .Any way the problem is the feed back rpm bounces all over the place and is totally unusable . I have the spindle speed averaging checked and the use the spindle feed back in sync modes checked i have spindle pulley set to 1 and use spindle motor out put checked as well as pwm. control, i get a good pulse as i have a led hooked to the pulse stream. Any one have any idea where i might be going wrong . Thank You