Profibus Master-Slave configuration settings

Hello again!

I have a little question for you guys.
I want to link two S7-300 controllers via Profibus (Master - CPU 313C via CP 342-5, Slave - CPU 317-2 PN/DP).
Could you please explain how to setup the address areas?




According to the snapshots attached, is it accurate to conclude the following:
1. CPU 313C
Input area: PIW 0 - PIW 19
Output area: QIW 20 - QIW 29
2. CPU 317DP
Input area: PIW 0 - PIW 19
Output area: QIW 20 - QIW 29

What are the basic recommendations for allocating the PLC memory? And what is the 'consistency' listbox?

If someone is interested, the answer is YES.
I've double checked this and come to the conclusion:
1. The column 'partner address' represents the Input (2nd row) and Output (1st row) area of the Master (in my case CPU313C)
2. The column 'local address' represents the Input (1st row) and Output (2nd row) area of the Slave (CPU315DP)

The only thing which is not covered is the 'consistency' option. Does anybody have any idea??

"Consistency" defines an area of memory that will be updated together. Setting the consistency to all means that, in your case, all 20 bytes should be read and written together. If, for example, you write to PQW 0 you will open a constency window that will not be closed until the last byte of the area is written.

If you want to read/write to individual words in different places in the program then set the consitenct option to "UNIT" rather than "ALL"

Nick

Thanks Nick! Great answer!

Just a note, this will be standard IO, I and Q as far as addressing is concerned, no need for additional blocks and no programming referencing to PIW or PQW areas.