How to make looping process in actual time with step7 programming

Hai friends...
I need some help from you.
I work with Siemens S7200 and step7 Ver4.0 programming.
There are 2 problem:

1. I want make a looping process in actual time....using FOR - NEXT.
For example I want 0.1 second for each looping process, so for 100 process need 10 second.
So I will get a data every 0.1 second during looping proccess.

in STL :
LD SM0.0
FOR VW125,+1,+100
bla...bla...bla..
NEXT

2. I want make a looping process continues (no limit).
I don't know how in s7200 the looping process limited on 2000.... So how to make no limited looping???

Thak's before

Detail

Do you know, what I mean???
1. Each loop must execute in 0.1 second.
For Example :I have y(t) as a output from a function, where t is time. with loops I need the value of y(0.1)? y(0.2)? y(0.3)? and so on...
(I try with FOR-NEXT)

2. I need loops that function (no 1) become unlimited. So I get y(0.1),y(0.2),y(0.3),.......,y(I stop the program).How the program???

Please Give me the solution in LAD or STL STEP7-Microwin.
Thanks before

Looping

There is no looping statement. PLCs are for real-time operation and looping might take forever.

You need to write code that calculates the new value, then set it up to execute on a 0.1 second interrupt.