ET200SP vs S7 PLCs

Hello dear collegues

I need some help 

In Brazil is very normal use ET200SP as PLC. In my work we've a lot of automation did with ET200SP without an PLC. 

My question is: is this right? can we use an ET200SP as PLC without problem? In a pratical way what is the difference  

I was loooking ET200SP datasheet and for me it's work as a PLC. There are DBs, FCs, FBs, Ladder... 

Thank you. 

Hello,

Perhaps the following Manuals might help:

1-SIMATIC ET 200SP Manual Collection

2-SIMATIC ET 200SP Distributed I/O system