Step7 - Subnet-IDs in Multi-project

I need to send messages via Ethernet to one Station in a Multi-Project from all the other Stations in the Multi-Project. It tuurned out that one of the Stations had a different Ethernet Subnet-ID from all the others, so I couldn't set up a connection to that Station. I decided to change the Subnet-ID of the offending Station to be the same as the others, but on compiling after the change, I got a load of errors complaining that physically different MPI and Profibus networks had the same Subnet-IDs. Apparently because of this "fault" I'm not able to download the system data with the new Ethernet connections to the PLC.

The MPI and Profibus networks are indeed physically separate for each PLC, so I'm wondering if I can simply change the Subnet-IDs so that they are all different, without causing any problems?

Are there any rules concerning the Subnet-IDs? The helpfile seems to imply that one can use any old numbers or should the "Project" part of the number always be the same, even when the Networks are phsyically completely separate?

Thanks in advance,

Roy

Roy

If I understand you correctly, you should have no problems changing the MPI and DP subnets, so that they all differ.

I can't get my head round the fact that you changed the Ethernet subnet of one PLC and netpro return the errors you descibe.

Are all these PLC's part of different projects that you have 'joined' together as one multi-project or are all the PLC's now part of one project with a number of MPI and DP networks, but only one ethernet network.

I am working on a project at the moment that has 38 PLC's with there own remote I/O. The remote I/O are on their own DP networks, but all the PLC's are on the same ethernet network. I did have a quick check and notice that the default subnet masks of all the DP networks are different.

Paul

Are all these PLC's part of different projects that you have 'joined' together as one multi-project or are all the PLC's now part of one project with a number of MPI and DP networks, but only one ethernet network.

Click to expand...

It's all one Multi-Project, but I have the impression that each PLC (8 in all) was initially created as a separate, individual project and were then all joined together afterwards. As a result most (all? can't remember now) had MPI Subnet-ID 0231-0001 and Profibus Subnet-ID 0231-0004 - I assume that the -0001 and -0004 are Step7 defaults.

I've now modified everything and it now compiles without any errors but I'll have to wait for the next Shift meal-break before I can download the System data and try it out.

I did have a quick check and notice that the default subnet masks of all the DP networks are different.

Click to expand...

Sounds like somebody else had the same problem!

Cheers

Roy

I wrote.....

plucas said:

I did have a quick check and notice that the default subnet masks of all the DP networks are different

Click to expand...

To which you replied....

RMA said:

Sounds like somebody else had the same problem!

Click to expand...

What I meant by that was that Simatic Mangler set the subnet masks all different, I didn't change anything

Paul

What I meant by that was that Simatic Mangler set the subnet masks all different, I didn't change anything

Click to expand...

If I interpret that correctly, then I guess that means that you (or somebody else) created the project as a Multi-Project from the start, whereas in my case it looks as though each PLC was handled as an individual project and then at the end all these were combined into one Multi-Project.

Cheers

Roy