s7 300 analog signal

how can i used analog signal by s7 300 and the addressing please

Hello mas-2000;

The addressing question is easy to answer: the HWConfig editor will set (allow you to select, if this is an analog module card) the addresses for the modules available. Generally analog addresses are in a range above 256 (digital addresses start at 0).
Each analog channel uses one 16-bit register representing the analog value; these values are not read into the process input/output table so they mare accessed through "peripheral" read/writes: inputs are PIW256, for example, outputs are PQW272.

Generally, an analog input card needs to be configured (software, in HWConfig, module properties; sometimes in hardware, if there are range modules to be selected and set). Details for each analog module in the S7-300 catalog is slightly different, and should be examined in the "S7-300 module data" manual (download it from the Siemens support website).

Moat modules will give you a numerical value between 0-27648 (unipoar signals) or +/- 27648 (bipolar signals) for the analog signal conneced to the channel; anything outside this range is over/underrange signal. The easiest way to handle them and scale them to engineering units is to use the integrated "SCALE" and "UNSCALE" functions, that you can find in the TI-S7 converting blocks library of the program editor of Step 7 (FC105 and FC106, respectively).

This is a very general view of using analog modules in Step 7; please indicate which model number yopu plan to use, what analog signal type you would like to connect (4-20 mA, =/- 5 V, PT100), so we may answer more precisely.
Hope this helps,
Daniel Chartier