Hello Everyone!

I've got an ancient (well, 1999-vintage) Mori-Seiki RL-253 twin-spindle, gantry loader-equipped lathe running a Meldas 60 controller.

To co-ordinate the actions of the lathe NC and the robot/loader, there are multiple M5xx series M-codes used. Some are to co-ordinate the Left Side (LS) of the machine (Namely M501-M504) and others are for the Right Side (RS) (Namely M506-M509).

I've found in my ladder that the codes are side-specific.

What I can't find out is what the difference between them are. I don't know why Mitsubishi/Mori would need four flags per side, if they were all the same. If that was the case, wouldn't 2 be enough for semaphore duty?

I was wondering if anyone out there had experience with a lathe/controller like this, and had any insights on these M-codes.

Thanks!