S7300 analog addressing

All,

Just a really easy question. I've got an application with an S7300 that will utilize various analog modules. I know that an analog input will by default take the shape of PIWXXX address. My question is, can PIW and PQW have the same number, and what is the first address that these can occupy. For example, can I have both a PIW256, and a PQW256 in the same address table. Also, just as important, is it possible to address the first as PIW0, PIW1, PIW2, etc. Thanks.

Russ

PIW/PQW can have the same number.

You can allocate any free address (for your CPU's range of I/O space).

Convention is to put analogues at 256 and above.

Thanks a bunch!

see title

Also, just as important, is it possible to address the first as PIW0, PIW1, PIW2, etc.

Click to expand...

You should be aware that the Step7 addressing is Byte orientated. his means that PIW0 occupies PI Bytes 0 & 1. PIW1 would occupy PI Bytes 1 & 2, thus overlapping PIW0. It's a good idea to stick with the convention of starting WORDs (and DWORDs) on an even Byte to help avoid this.

This applies to all addressing within Step7, ie also Marker and DB Bytes. For example, a REAL stored in MD100 would occupy Bytes MB100 - MB103.