S5 to S7 profibus

Hi,
Got one project to do. I need to extend existing S5 system with S7 CPU315-2DP.
I have to make PROFIBUS DP connection between S5 and S7 and make some corrections on S5 programm.

I have no experience with S5 at all. Im asking for information where to start and what do i need to set up Profibus connection.

On S5 side i have: 115U cpu943b equipped with a CP 5431
On S7 CPU315-2DP with I/O modules

also i have Step5 V7.23 and old system program.

For S7 i have all software needed

how much data?

The easiest way to link Siemens PLC's without having to use special blocks is to use a DP coupler, this is a low cost interface which both PLC's use as standard I/O, its like having an output card from each PLC connected to an input card to each PLC, only more data can be transferred.

S5->S7: ~30 bytes
S7->S5 ~500 bytes (mainly process information to output to Operator Panel which is connected to S5)

Maybe if i can connect Operator panel to both controllers, then i need to send only ~2bytes between S5 and S7

My OP is: Mitsubihi E700 connected to S5 PG/AS511 on RS422

Is it possible to link both PLC's without any additional hardware? Only CP5431 on S5 side and CPU315-2DP on s7 side.

If not, then is it OK to use CP342-5 on S7 side. I've found nice howto for setup FDL connection at http://support.automation.siemens.c...&viewreg=WW&nodeid0=10805982&objaction=csopen