Lathe lead screw block diagram, and a confession

[tony ennis]

The confession is that I don't have a clue what am doing. Figuring it out is half the fun, of course.

Block 1 is a 'pulse generator' attached to my lathe's spindle. This will likely be a disk full o' holes, an LED, and a phototransistor. The output is a stream of pulses directly related to the spindle revs.

Block 2 is a PLL that multiplies the frequency of the pulses from Block 1.

Block 3 is a virtual quick change gearbox. The input comes from the PLL. The VQCGB is nothing more than a multiplication and division of the input pulse frequency. The CPLD will be the main player here. Two switches - a 6PST and a 9PST - control the division parameters. The output is a pulse stream.

Block 4 is *something*. A stepper controller? This is where things get dicey in my brain. I have done the math up so block 3 is generating the right number of pulses assuming 200 pulses makes the stepper go around once.

Block 5 is the physical stepper and its power supply.

Would someone mind clearing up what the stepper controller in block 4 really is, how it relates to the motor, and how much of it I really need to worry about?

How does Block 4 relate to Mariss' CPLD tutorial project?

Thanks for the infoz!