Possible retrofit of a Körner Magic550 CNC Machine

Well there are all kinds of serial interfaces. CANbus, Profibus, Sercos are the better known ones but there are others, using proprietary protocols. Trying to get yours to work with linuxcnc would require _serious_ research just to figure out the protocol used, let alone the work needed to actually implement it.
PWM is possible, I think, but you would need to link some documentation to the drives in question so the mesa guys can have a proper look at it.

Not much information on the Heidenhain drives.  Can anyone recommend a alternative servo+drive combo to the motors that are now in the machine. I have attached all the info I have found.

I attached the link to the manual for the Heidenhain servo drives which are compatible with the QSY motors that are installed in the machine . Maybe someone can shed some light on how these communicate with the pc. UM310 is the drive that is of interest . 

www.heidenhain.it/fileadmin/pdf/de/01_Pr...OEM_ID1303180_de.pdf

HEIDENHAIN-Umrichtersysteme
Die Umrichtersysteme der Antriebsgeneration Gen 3 von
HEIDENHAIN sind für den Betrieb an HEIDENHAIN-Steuerungen
mit digitaler Drehzahlregelung und Kommunikation über GBit-HSCI
geeignet.

Sound like it uses HSCI bus for communication. Never heard of it but I'm pretty sure that is a nogo with linuxcnc.

I did some googling and there’s nothing about HSCI . Heidenhain are really secretive about their stuff ,no wiring diagrams ,only the basic information. I guess it works as a business model.
i think at this stage there are 2 options to choose from.
1. Go with Heidenhain drives and TNC Controller ,probably very expensive  
2. Strip everything out and install another servo-drive combo and go with Linux+Mesa ,probably very time consuming 

After some extensive googling  and some back and forth with some Servo+drive manufacturers we are still searching for Motors and drives. In the mean time we striped everything of the machine and we found that the installed Servos were smaller than the ones specified in the schematics.
All the servos are the same ,Heidenhain QSY96G which have 1,4Kw and a moment of inertia of 6,3kg*cm2..I have found similar servos but with about 25% less moment of inertia. Does this influence noticeably the acceleration/deceleration ramps ?
Another thing that I found out is that servo motors, annoyingly, don’t use the NEMA sizes .It’s like the potatoes in an organic food store, everyone a different size.
I am gonna put here the specs of the QSY96G servos maybe someone can help me find suitable Drives .
power 1,4Kw
voltage 291V
current 3,3A
torque 3Nm
max current 25A
max torque 22Nm
moment of inertia 6,3kg*cm2
encoder incremental 1Vss