You can cheat and use peek and poke to read and write Input and Output addresses.  This is dirt simple and you can basically loop through all conceivable I/O you would use, and mark the lowest and highest and any holes you may not be using.

For s7-1200, you will by default having 0..1. 

hl123456

Hi to all,

I'm looking for a way to determine the byte number of the first digital output card, and same for the last card (i.e. if my first output is 6.0 and my last output is 14.7, I want to get 6 and 14).

It has to be done independently of my hardware configuration (my code must be executed on any S7-1200/1500 CPU).

First : is it possible ?

Second : do you have any suggestion to help me doing that ?

I've found the RD_ADDR instruction but it seems to be hardware depend... could we get ride off this dependency ?

Maybe with the IO2MOD instruction ?