What a number of replies in thread! Cheers guys. I know that many of you are gurus when it comes to delaing with this kind of problems. However I thpught that PIW xxx is the only way to address analog inputs. In my PLC configuration I have one DI 16x, D= 16x and AI bx12bit module. When I placed that in hardware config editor, I got address for AI module from 288 to 303. I've read somwhere that analog inputs are in format PIW xxx and that Step 7 is interpreted them as integers between 0 and 27648, so naturaly I've used PIW288 address for first channel on the module. Now reading this, it seems that this channel can be also addresed as IW288, I didn't check it, but I will tomorow. Where can I lear a little mora about this? For example when to use IW and when to use PIW? Would it be OK to every question I have place in this forum? I know that some questions will seem stupid to you but... I didn't have any training with Siemens equipment, so basicaly many of things I know, I've learned on my own.
Thank you all much for help and I'm glad that there are a lot of people here who wants to help.