Connect to step 7 plc over profibus and ethernet help

Hello all, I am hopeing someone on here can help me. We currently have our plcs connected to an ethernet network, connected to this is a desktop pc which I use to go online to the plcs (Siemens step 7). We are getting a new line installed and this is going to connect to one of the plc's existing profibus networks which already contains inverters, et200's etc, the new line is going to have inverters and et200's etc as well. My question is will I be able to go online to the new plc via the ethernet network to the original plc and then over the profibus to the new plc? I seem to remember in the distant past being told this wasn't possible? Also along the same lines we have SCADA connected to the ethernet network which we use to run the plant, will this be able to connect to the new plc in the same way as the desktop? I'm pushing for an ethernet connection to be installed on the new plant but it doesn't look like its going to happen for some reason.

Thanks in advance for any help you can give me.

It is possible if all the devices in question support routing.
You have to create a common STEP7 project that includes all the PLCs in question and also either a PG/PC Station or a PC Station that represents your programming PC.

But there are many reasons to NOT put several masters on the same DP network.
The bus update time will drop significantly, an single error can take down both masters, and the whole thing becomes very inflexible.

If this is a new project, I would demand to use ethernet,

Thanks very much for the reply, think I'm going to push a lot more for the ethernet! I cant really understand the issue an ethernet card is minimal expense really!

One other quick question how will this work with SCADA will that be able to access the new plc through the old plc??

Thanks again.

If the SCADA is a Siemens WinCC or uses Simatic Net, then it can use Routing to the new PLC via the old PLC.

Thanks sgain Jesper. Its great there are people out there with the knowledge who are happy to help others not so knowledgable with no benefit to themselves!

Blue Fox,

I humbly beg to differ from your comment that people are happy to help others with no benefit to themselves.
Believe it or not they feel fulfilled and content when they see that not only one but many readers can benefit from their input.

ali