This retrofit is possibly the easiest retrofit of all mills. I used a 7I97T with the existing servo dives and VFD.Notes:1. Aside from the servos and VFD there are only five 24V miniature relays to control.2. Since the servos utilized a tach (Aka Resolver) drive tuning took minutes to tune.3. The only additional board I made was transistor board to provide a signal to the J425’s drive enable relay. The drive enable optocoupler on the 7I97T cannot provide sufficient current for this miniature relay. This board consisted of a P-Channel Mosfet and a 10Kohm pull up.4. On the J425 all of the axis limit switches and the Estop are all connected in series to a single relay.5. I was able to use all of the existing wiring. I didn’t have to cut or splice any of the existing wiring.6. Almost all of the wiring to the 7I97T was through the existing DB connectors.7. Just like any other CNC, you’ll need wiring diagrams. They are available from
zpsusa.com/kneemills.html
I did not have any issues with the installation or performance of the Mesa 7I97T. I was concerned on its ability to thread mill since it requires 3 axis’s synchronized. It wasn’t an issue at all, in fact I cranked it up to 120ipm without any following errors.
