I am thinking of getting one of those Vista CNC controllers and I need a mode where my program is set to run and as I turn the encoder, I get two things, the program is running and in a ratio that is dependent on how fast I am turning the encoder.  Turn the encoder fast you get 100% of program speed, turn it slower and the feed slows down.  I need to be bale to set the spindle speed separately in the speed override so I get a happy median for slow feed and programmed feed.    

You are looking for  Shuttle mode. Best to talk to Vista about it "BEFORE" you buy it as it is LESS than perfect in Mach3.

(;-) TP