I have a Bridgeport Interact mill with a three phase spindle motor on a VFD.
In addition, the mill has a vari-drive system with SPEED INCREASE and SPEED DECREASE selector. This selector activates pneumatic solenoids that drive an air motor. The motor actually increases and decreases speed of the spindle by adjusting "vari-discs". For spindle speed feedback, and rigid tapping, I will install a US Digital encoder on the spindle, which is very easy mechanically. I use PPMC as a computer to machine interface. So, with these facts in mind, my question: Can I somehow control speed from G code by controlling these solenoids? Say, I say S3000 and drill. Then I change tool to a tap and say S300 and rigid tap. To accomplish that, EMC would actuate SPEED DECREASE solenoid and wait until the output speed, as reported by the encoder, approximately equals the commanded speed. This would not really need to be as precise as a servo motor with closed velocity loop on the drive. Just to be close enough to be desired speed, say if it is 295 to 305 RPM I would be fine. What EMC elements would I need to use to accomplish that? Is that even possible? Has anyone done this? I do realize that it is a "Mercedes Benz" type feature (as opposed to a "Yugo" use of a VFD), but hey, if I can have it, it would be great. If you know of anyone who did that or sample configs, it would be awesome. Thanks guys. i ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
