How to get Profibus Topology?

Hi Guys,

CPU: S7 414-DP, Siemens.

How to get Profibus Topology? In HW config and Netpro I can see what devices are connected to the profibus. But it does not tell me the order of the devices that the profibus cable connect.

Thanks,
Sam

Read the projects documentation, that is why it is there.

Do you mean how to detect it automatically ?
You dont have that with NetPro and/or regular Profibus hardware.

A Profibus analyser such as Profitrace can automatically detect both devices and cable lengths, and the order they are interconnected.
The topology detected in this way is only to analyse problems and for documentation.
It has no influence on the setup of the profibus network.

RussB: Which document are you referring to?

Jassper: Yes, automatically. In Netpro, there is an option in PLC>PROFIBUS>Show Network Topology. Isn't there any useful information about the order of devices here?

I've got another question as well. There are some other stuffs in Netpro which I cannot see them in HW config.(See the picture pls), I think they are ports for HMI connection. But Why two of them are not connected?

Thanks,
Sam

The PLC>PROFIBUS>Show Network Topology requires a diagnostic repeater in order to analyse the network and figure out the toplogy. Similar to the Profitrace device I mentioned before.

If the devices are not hooked up to anything in NetPro, then open the HW Config of each device and check the port in question. It will probably show "not networked". You can then specify the network for the port in order to reflect the reality. Dont add them if they are not really connected. For Profibus, the types and number of the devices drastically affect the calculation of the TTR which is the main Profibus Bus profile parameter.

Thank you very much Jasper,

In fact there are three diagnostic repeater on the two network of the PLC. This is when I go to Show PROFIBUS topology. ( see the picture please)

On top left corner it says "The following nodes cannot be assigned" and on the diagnostic repeater there is sort of error indicator, and says "Readout of the Topology is not supported".

Does that really mean the Diagnostic repeater has not the functionality of detecting the topology?

Thanks,
Samad

I have used the Profitrace analyser, but never a Siemens diagnostic repeater.

From the help in STEP7 for the Show Profibus Topology function:

Prerequisites
· The PROFIBUS subnet is equipped with Class 2 diagnostic repeaters as of order number 6ES7 972-0AB01.
· The diagnostic repeater can be accessed online
· The diagnostic repeater, the PROFIBUS subnet or the DP master system to which the diagnostic repeater is connected is selected.

Click to expand...

Find the documentation for the diagnostic repeater and follow the instructions in there to the letter.

Thanks for the help Jasper. I follow it up.
Sam