S7 Ethernet problem

A colleague has asked me this question, can anyone help us here?

I have a "Data collection" PLC (CPU314) with an ethernet module (CP343-1 lean). My requirement is to read data from 3 other PLC's on the network,
a) "Rotopacker PLC" (CPU315-2 DP).
b) "Palletizer PLC" (CPU315-2 DP).
c) "Bag applicator PLC" (CPU315-2 DP).
all with ethernet modules (CP343-1 lean).
I need to read a datablock from each one. The information will be correlated into a data block within the "data collection PLC" ready for SCADA to read and generate a production report.I am following the support example of the Get Block in which S7 communication are used, however I get an error in Netpro when i select S7 comms, if I select tcp/ip all is ok. With tcp/ip selected no connection is shown in the GET Block connections, if I select a new connection I end up with an error.

The 3 PLC's I am reading from are under warrenty from another company, so I am not allowed to modify them, but I am allowed to download to the hardware configeration (managed to get permission for this due to IP address changes).

Each remote PLC only has about 40 bytes of data in the datablocks I am interested in.
I am currently programming the "Data collection" PLC offline and away from the site.

My first question is am I using the correct block (Get Block) to begin with?
if so do I need to bother with S7 communications or just use tcp/ip.

Hello JohnW.

The problem is that the "lean" CP343-1 can only be a "server" when using S7 protocol. That is Siemens lingo for saying that it cannot initiate a comms job.
That again means that you cannot use PUT/GET.
This little tidbit of information is well hidden in the specs.

The good news is that it is still possible with SEND/RECIEVE or FETCH/WRITE jobs with TCP/IP protocol in stead.
You may have to check up on if you have the right standard blocks, as there may be a new or a special version for use with the LEAN module.
So possibly it can be done with FETCH and no need for changing code on the other PLCs.

edit: I made it a bit more clear that is is only with S7 protocol that you have the problem.

Thanks for your help Jesper. Her is the reply from Siemens;

1. You cannot use the PUT and GET commands with the CP 343-1 Lean. You would you need to upgrade to the full version of this card to use these commands.

2. Alternatively you could use AG SEND and RECIEVE. However this would entale you having to modify the code in the PLC which you state you are not currently allowed to do.

It looks like we will have to up grade to CP343-1EX21.

Hi JohnW.

I also learned something new. I thought that it was possible to use FETCH/WRITE between S7 PLCs. It turns out that the S7 PLC can only be a server for FETCH/WRITE, and that it is intended for use with S5 or other non-S7 systems.

Anyway, remember you only have to upgrade the CP343-1 in the datacollecting PLC, not the others.

Thanks for the Help Jesper, that was the same as we were told by Siemens technical support, which is very good in the UK.

We will have to buy a CP343 - 1ex21 or 1gx21 for our data collection PLC.