S7 Profibus in HW Config

Hello,

When using PLC_SIM I had to change the MPI/DP setting to MPI on my 317-2 PN/DP in HW config to be able to download. I realized later, when connected to the real PLC that this removed the link to the bus where all my slaves are connected.

How can I reassign my CPU as Master again?

Now my slaves are connected to a Master system with no master and when changing to DP on CPU a new master hanging in the air appears.

Thanx in advance

I have experienced that sometimes the slaves automatically reattach when you set the port back to DP. But I have also experienced that it did not reattach automatically, and I couldnt get it to attach no matter what I tried. In the end I copied the slaves to another station, deleted the orphaned slaves in the original project, and then pasted them back into the DP network from the other project.

You may also want to upgrade your PLCSIM. From v5.4 it support simulation via DP and Ethernet, not just MPI.

Lost Profibus network

Hello, I had the same problem. The solution is as following:

Create a new profibus network.
You will get one existing PB network that is not attached to the master (the one with all the slaves attached), and one empty network that is attached to the master.
Click on the empty PB network, and press the DELETE button; delete this (new created) network.
Next, recall the bus properties of the master.
Now you can attach the network you want to the master.

I hope this will solve your problem?

Kind regards, John van Dijk

Thank you both. I will verify Johns solution later as it seems to be the better one, but have tried something similar to Jesper's already.

I exported the HW config from a recent backup, deleted the one in the newer project (CPU deleted but not program) and imported. It was then necessary to copy the unattached "Program" to the CPU in the manager.