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  Hello there. I have a couple of mills with Yaskawa servo systems, mid 1990 BE series analog drives. They are junk, constantly blow up, very little info available, only support from Yaskawa, send us your life savings, in my case about $5 , so not enuff anyway.Using another brand of drive should be doable, the wrinkle here is Yaskawa’s unknown initial magnet sensing. The motors are sinisudialy communtated, sorry for the misspelling. The oldest ac yaz motors used what I suspect is a coded type hall sensing for initial trapezoidal communtation. The output signals were v,-v,u,-u,w,-w. , output from the encoder to the drive.The new motors have the markings on the encoder for the added signals, they are unused. I suspect the circuitry is there. Both encoders have on the glass disk , an inner ring of what I guess could be grey code. See pictures.Does anyone recognize this and have a hypothesis about how these signals would work? My guess is they are similar to the red cap Fanuc bldc signals. I have not put a scope on them  



 

 I'm having an odd problem. I'm running a threading routine using G76. I thought that, while threading, I could change the spindle speed without affecting the operation. Everything seemed to be working fine until I starting threading something a little larger for me - a 1"-8. I started to see bad gouging off and on during the threading. that at times nearly stopped the (7HP) lathe. I was only taking off about 0.002" per pass for most of the operation. I thought something must be moving, and checked all the obvious things. Everything looked OK.

One of the things I tried was making a scratch pass at three different speeds, 100, 150 and 200 RPM. I ran the same program each time without changing the setup. You can see that the cut indexed to a different point for each speed. Conversely, if I ran it three times at the same speed, it would index to the same cut.



This is not good! It means if I cut a thread and then need to recut it, I need to make sure that the spindle speed is exactly the same or I'll get a different thread position. Needing to cut the thread again can be because the piece rotated in the chuck during the cut or I didn't set the tool X position deep enough. I'm also thinking that as the lathe slows down slightly, it might change the Y position of the tool incorrectly and cause the gouging.

Any ideas?

Two indexing signals to LinuxCNC: one pulse per revolution for indexing, and ten pulses per revolution for position
Spindle speed set manually, and not by LinuxCNC
LinuxCNC v2.9.3