I am sure can help you, but You need answer the question and give detail of your machine/system/application 

#1--Why do you want to change

#2--give the detail of your  machine, such as CNC, or PLC controlled signal axis, or ...

Attache picture of your Drive and power supply modules

S-BO!

Thanks for responding,

Basically i want to change the servomotor and the servo drive

SIEMENS 1 FT5064-0AF01-2-Z with a new servomotor and a new servoDRIVE

wich is equivalent to the old one ( same caracteristics Torque,Speed...)

With the one  page of Electrical drawing I can almost give you suggestion. But for better and accuracy --I need you drive HW configuration real picture--NOT drawing. including Power Supply module and you drive module and make clean of the following question:

#1--you said 6 tables, but actually how many servo drives (module) and servo motor you used?

#2--Is there someone or yourself to upgrade to S7-1200, I don't think original PLC is 1200, and after upgrade the system working good for some period or totally not working? are there any display./OP/HMI, are there any interface /module to receive encoder feedback for position or speed?

PS:#1 Let you know you servo drive possible called SIMODRIVE 610,( see my pic. attached) which I had worked as final inspector in the factory in Germany where made it  in the year of 1990.

PS#2 See Siemens  servo drive generation from  610--611---611A--611D---611U; then totally changed SINAMICS S120 for motion control (special for CNC 840D SL)

so answer my Q's then we continue