Not one can tell you how to do it, it is a very complicated function, I learned this in Siemens training center in Germany in 1998 (840D power line, but same function as 840D sl)

I have been a trainer and have trained the machine builder customer  in China, it was an 1.5 days context in the 10 day training, you must know everything --NCK, PLC (S7-300), NC programming and operating of 840D

    If you really want to try by yourself, I suggest you Google  manual --see the footnotes of manual page cut from that book-- FB1(P3)

there is an example for FB4, PI service, I suggest you starting from easy one such as "LOGIN'" , --set NCK password, THEN TRY SELECT (not LOAD PROGRAM BUT select program in NCK memory)

I can give you tips,

#1--in OB100, call FB1,DB7--the parameter NCKOOM:=TRUE is very important condition for  use FB2,FB3,FB4 and so on

#2--using conditional call FB4 (such as using an input button) 

jithumk

Can u please tell me how u done this, I am trying but i can't select function.