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General Mach Discussion / Re: Bridgeport Discovery 308 retrofit
« on: December 31, 2007, 12:41:31 PM »
The spindle drive can bet set to accept 0-10V signals as well. In the original machine while milling the spindle drive runs in RS422 mode, basically just getting the speed command. The drive uses separate encoders for velocity feedback (this encoder goes to the drive) and position (this encoder goes to a little circuit board beside the spindle drive). When doing tool changing, the spindle drive is set to 0-10V mode and another circuit board takes over to control. It supplies the analog reference and reads the secondary spindle encoder signals to properly position the spindle for tool changes. I have retained this original setup, but I think it would work just as well, perhaps, to run the spindle drive the whole time in analog mode. But, by retaining the original setup I have a spare 4th axis to use for a indexer etc.