Hi guys,

I'm upgrading an old Takamatsu lathe with a Yasnac 2000G controller to CamSoft for a friend.

The drive is a Servopack CPCR-QR756S and in uses a resolver mounted on the motor for feedback. Standard stuff.

The CamSoft board comes with encoder feedback, so it won't read a resolver, but there are things that we could do:

1) Drill and tap a hole in the end of the motor shaft, mount an extension shaft to the hole, run the shaft outside of the resolver housing, and connect an encoder to the outside of the resolver housing. Easy-peasy - and this is how we fitted encoders to our old Demag motors so we could control them with Thor vector drives back at Saturn. Worked great.

2) The Servopack board had a header with what suspiciously looks like encoder signals on them. I would have to put my scope on them to find out for sure (which I am going to do regardless, curiosity and all that). But I'm not keen on modding the drive...

3) A resolver to encoder converter. I've done some research, and I could get one for about $500. This would be the simplest way of doing things.


But how important is the position of the spindle anyway? The original setup couldn't have known what the spindle angle was, it was controlled by an analog speed reference, and reported its speed back to the controller via an analog output.

I'll have to look, but I'm not even sure if the belt driving the spindle is toothed (posi-drive belt). So how would it keep in time in the first place? I can only see an issue with threading, otherwise controlling the drive's speed is the only concern that I can see.


Please be gentle, I'm not a machinist, I'm a controls guy with plenty of time on his hands.


Thanks!

John