S7 add new hardware to profibus

Sorry if this is a beginner's thing but I'd appreciate a bit of guidance:

We are going to install a Teleservice adapter into an existing profibus network, the existing profibus has a loop left in by the original installers to allow simple installation.

I happy enough with fitting the profibus plug (with in/out connections) into the loop but my main concerns are:

How much isolation do I need on the bus before cutting the Profibus cable (is stopping the PLC enough or do I need to power down the PSU's) How much damage can I do, or are they short circuit protected?

Will the profibus automatically detect the new device and assign it an address or do I have to do it?

How to I configure Step7 to see the new device on the hardware layout

Thanks for any help you can give
S7-400, Step7 v5.4

Well, I can hazard a guess to your first question.

Never cut a multiconductor cable while it's powered up!

Our IT guy did that a few times with cat-5, said he's fried many switches or hubs that way.

Check in the Profibus connector that is plugged in the master PLC, if the connector is with a PG socket. If it is then you just plug the cable from the TS adapter into that PG socket. No need to cut the Profibus cable then.

Not sure, but I think that the TS Adapter needs 24V from the PG port just as an almost similar PC adapter does. If this is the case, then you cannot just put another Profibus connector somewhere in the middle as a tab to connect the TS Adapter to. With the normal purple Profibus cable with 2 wires, the 24V in the PG port is not used. In other words, you have to plug the cable from the TS adapter in a port with a PG socket as described above.

There should be a software package for the TS adapter. One of the things that it does is to allow you to set the MPI or Profibus address.

Thanks for that info, the Teleservice adapter has a separate 24V connector,m which is easy enough to do, so I assume it get all its power from that.

Do I have to configure the teleservice adapter address while the PLC is in stop or wait until it's running again?

Aha. Didnt know that there is a separate 24V supply on the TS Adapter.

If the Profibus network isnt running at the maximum speed, 12Mbaud, then it is normally possible to add or remove a programming PC without problems. Dont know if a TS adapter even supports 12M.
Notice that there is normally reserved resources for 1 PG connection. If you have more than 1 programming device on the network, then the profibus configuration should be updated. You should add a PG/PC station that represents your programming device. That in turn means that you have to download updated HW configurations to all masters in the network. And that can not be done without stopping the affected CPUs.

edit: I notice that you originally asked about the need to shutdown the PLC.
I dont think that there will be any electrical problems. But as the Profibus network will definitely be interrupted, you have to shutdown the system anyway.

thanks for your help, much appreciated