Thanks for the replies guys.
The reason I want it to update so fast (ideally every millisecond) is that I control the servodrive directly with the PLC. The PLC has a built in motion controller that runs on 1 millisecond. The servo position is coupled to the external axis position that is sent by Kuka. I don't just send the target pos to the PLC but the actual position, and couple the servomotor to that position. If the update only happens every 12ms the motion is 'stuttering' (for lack of a better word..), I have solved this now by applying a 12ms filter. This works with the only drawback that the motion lags 12ms behind what it should be.
In hindsight, this might have been a better solution.
Just to clarify, there is no real necessity to update the position this fast for this specific application, but I would like to know my options if I ever encounter a similar application where I do need the fast update.