In our application (T-CPU) we will gear absolute (technology functions) to an external encoder.
We don't know at the moment what type of encoder it will be (incremental, absolute, profinet RT, profinet IRT).
If it will be incremental,what IO-card will we need on our S71500 TCPU?
What card if it would be absolute Endat?
Can I link an external encoder object directly with an fysical encoder on Profinet IRT, and also on Profinet RT?
Or in the case of Profinet RT, do I need to write position value to encoder in servo cycle?

HEllo,

If your not able to configure encoder as technology object 

you can use data block for encoder value(position) update ,there is standared Data block with Telegram 81 as data type 

Refer attachment for data block details 

For me its working fine