Buying a used Mikini

[mcphill]

Making some headway, here is the current version of the schematic:


I have debugged it and all seems to be working in manual mode (I don't have the VFD yet, but the F/W and Run/Stop work, as well as a readout I put in for spindle speed, Z-bit, and an 84 ppm signal for the Mikini). Only hiccup so far is M3 and M4 don't seem to switch to RUN mode when in Mach control. May be a function of the VFD not being installed, though, so I am not too worried yet. I actually did all the programming of the Arduino myself after a bit of a training session with my work buddy. It's been fun! I added a small OLED screen to read out the modes and the spindle command and and actual speed so I have a bit of diagnostics feedback.

The PWM signals from the Mikini and Mach3 are so slow I am able to convert the PWM to spindle command speed directly in the Arduino instead of using a PWM to analog 0-10 v box. The box didn't work well since the signal was so slow. I think the Mikini is 8 hz, and Mach3 is set to 25 hz. The box wants 100 hz but would prefer 1 khz! It was a bugger to figure out how to parse the PWM signal in C, but I figured it out!!!

[Tinmuk]

Interesting approach, I had thought about doing something like that, but then I just went ahead and bought a Centroid Acorn and DMM servos. Very easy conversion, except for having to cut out the casting to get to the Z motor. I had to buy a bigger angle grinder to get thru the thick casting. Still need to put the new Z servo in...

I did replace the Mikini BLDC control after I accidentally shorted it out.
I bought a new BLDC drive, but I still have the Mikini motor and it works fine.

The second Mikini I bought was converted to parts from CNC4PC, but I'll go ahead and switch to Centroid so it matches my existing Mikini and Hardinge Accuslide (also DMM servos)

I tried Mach and found it to be very difficult to use. The Centroid software is great and actually makes sense to me. It's more like the Haas and Fanuc controls I ran before I retired. BTW I was a prototype machinist for 42 years and design engineer for 20.