Weiler 160 CNC Retrofit

After years of using a very old (1930) and worn out lathe, I decided to get myself something new.
Found a Weiler 160 CNC in very good condition (400 spindle hours) that has been used lightly in a school. The buffer battery is dead and the screen does not turn on anymore, so a perfect project for a retrofit.
The documentation is one of the best I've ever seen, everything from bearing preloading up to motor change of the toolchanger is described. Tons of drawings from every part. The whole machine just screams german quality.
 
 

Only thing I'm not really sure about is the measuring system. It uses incremental encoders with 6 signal pins instead of glass scales. Does anyone know how I connect them to the mesa cards? Can I use the normal encoder inputs for that or do I need something else?
 

They look like 'normal' differential encoder outputs.  A/A-, B/B-, and H/H-... with H being the once-per-rev index signal.

Should be a standard Mesa connection.

Are those encoders connected directly to the ballscrews, or to the motors?  What's driving the motors?

 

Aah of course, H is the once-per-rev signal. Somehow didn't occur to me, but now it makes sense, thank you!

They are connected directly to the ballscrews, the spindle encoder is connected via belt. They use "Heldt & Rossi SM 807 DC" servo drives for X and Z and a "Baumüller BKF 12/70/400" for the spindle. Controller is a "Sinumerik 3T".

 
 
 

I'm not personally aquainted with those drives, but a quick internet search makes me think they're analog-input DC servos.

Hopefully someone with more experience will jump in, but you could probably take your pick of with re-using the drives with an analog Mesa, or switching to modern AC servos (with analog, S&D, or field-bus/Ethercat).

Nice lathe, by the way.  You'll be giving RotarySMP's Schaublin 125 a run for the money.

Yes I'm pretty sure they are analog input driven.

I'm planning on using the 7i97T with another card for more I/O. Was planning on using a 7i84, but I can't find them anywhere in stock. I need 20 sourcing outputs and 25 sinking inputs in total.

I could use some relais to convert the sinking outputs of the 7i84D to sourcing ones, but that seems unnecesary complicated. Other option would be the 7IA0 or the 7i77 but they are both 150€ more expensive.

For the controller I'll probably use a Raspberry PI 5.

Found this vid:

In the comments the author discusses replacing the XZ motors, but keeping the main DC spindle motor.

Might get some ideas - other than using Mach, of courseimage missing /media/kunena/emoticons/wink.png

Regarding the extra expense of the available Mesa cards... I don't know your situation, but that amount of money seems pretty trivial to spend on what should turn out to be an amazing lathe.  I know you'll spend more than that on just a few tools.

As for the 7i74 vs 7i84D... Small DIN-rail solid state relays are getting quite cheap (no flyback diodes required) to flop your output signals.