Profibus DP communication between two PLCs (315-2 DP)

[PawelStrzelecki]

I’ve just come back from lab.

Thanks to yours tips I manage to use SFC 15/14 to send/ receive data. The main errors where the wrong LADDR parameter and error in HWConfig and RECORD parameter – there should be the same number of bytes.

Now I’ll study I_PUT/I_GET (probably till the end of the week I’ll have new questions

).

Thanks again.

PS Does anybody know how many bytes can be sand this metod with SFC 14/15? 32 bytes?

 

[gregoryg]

For S7-300: as many as you can configure for one slot in DP slave (depends of its type) and not more than 244 bytes (Profibus limitation).
For S7-400: up to 32 bytes.
If you reqiure more data you have to configure more I/O areas for Slave for ex. 2x32bytes but there is still limit of 244 bytes In and 244 bytes Out total.