2 Master PLC's and 45 slaves on same Profibus

I have a profibus network with 45 slaves (S7-314C) connected to it. Also there is a Protool visualisation connected to it (only to the master, not to all the slaves)

Now I have following problem:
My client wants a second Master as backup with a second Protool. When one plc/Protool is malfunctioning, the other can control the slaves. I tought of doing this with with Direct Data Exchange, but that only supports 32 connections, is there an other way of making this work?

Wow. That is a lot of DP slaves on a measly 314C. It is not clear from your post if the HMI is connected via MPI or via DP. If via DP, then it will all run nice and slow.

1st. Direct Data Exchange works with CPU-to-CPU via MPI only. It has nothing to do with DP slaves.

2nd. You cannot make a permanent installation where there are 2 masters with the same DP address, and you cannot configure a DP bus where 2 separate masters control the same DP slaves.

So, you are trying to create a discount version of a redundant installation.

There is an option package for S7 that makes a software-based redundancy with 2 CPUs (6ES7862-0AC01-0YA0).
The good news it works as you intend with even an S7-300.
The bad news is that the DP i/o must be with IM153-3 modules. IM153-1 wont be enough.

edit:
Siemens website mentions both IM153-2 and IM153-3. It is not clear to me which one is the correct one. I think IM153-3.
Here is the manual for software redundancy:
http://support.automation.siemens.com/DK/view/da/1137637

It is the kind of requests that should be asked before a project is commisioned.

The Master PLC is a S7-319, it wouldn't really be nice to have all this on a 314 ;-)

I was in the impression that Direct data exchange did work over Profibus, when I try to configere it, it asks for a profibus adress, so I guess it would work.

The two master plc's don't need to have the same DP-adress, they just have to be able to control all the DP-slaves (send and receive data)

The 2 HMI's would each connect to one master PLC via profibus (or MPI, doesn't really matter) and both need to show axactly the same and control the same (the master plc acts as data concentrator, and redirects all data from and to the slaves because you can only configure 8 connections in a Protool or WinCC flex project)

The software redundancy is not what I need because there's allready 314 plc in the installation and these plc's have the logic of the switchgear in them, they need to be able to function without the master PLC.

I know that, somehow, this is possible to realize, just need to find out how.

My bad. I missed the part that the slaves where 314C's.

About Direct Data Exchange:
Are you possibly talking about the DDE that can be configured between intelligent slaves ? That would be possible to configure on your system with 314C slaves. But it is of no use for your application though. This DDE is used to exchange data between intelligent slaves without having to manually program it in the master.

That it is 314C's and not ET200M's does not make it better. It is impossible to configure that slaves have more than one master. And it is impossible to have 2 masters with the same DP address.

You could possibly have a crude system of physically switching between the two DP masters. But for some time during the changeover the DP slaves will be without master.

One real solution could be to install an additional CP342-5 in each 314C rack. Each station can then have two DP slave ports, each connected to separate DP networks and masters.
You must then in code make some way of deciding which DP network must be the active one.
All this will in effect create a similar software based redundancy as is possible with ET200M.

I think I like the solution with extra CP342-5 the most, but that's going to be expensive. Have to check it out and take a good look at it.

If it turns out to be too expensive, i'll use some kind of profibus switch. Maybe by powering a OLM (wich is availible already) for the active master PLC.

Using the profibus repeaters to change which master is connected should be possible. Just cut the power to one repeater, wait 1 second, then connect the other repeater. Each of the PLC could control its own repeater in code. And you could electically interlock the relays so only one can be active at a time.
However, when switching from one to the other, for some time the slaves will be without master.

I've just talked with the project manager and it will probably be the repeater option. Not 100% sure however.
First I'm going to create a mok-up, to test some things.
The couple seconds delay isn't a big problem.

Thanks a lot for the help.