Hello!

I meet some problems with profibus and need help from experts. 

Is used PLC S7-400 with CP 443-5 Ext as master profibus. This network contains 97 slaves. Most of all are ET200B, ET200M and PP17. Baud rate is 187.5Kb/s. Total length is around 1500 meters. 11 Reapeters are used in this network (successive maximum 6). For diagnose is used FrofiTrace tool. All segments bettwen reapeters was tested and signal is strong, no reflection, no short circuit and wire break. But in some times profibus get down, not all but only several stations, different times - different stations. In attached screens you can see print screen of diagnostic diagram.

On procentec site I found this FAQ: 

procentec.com

Can I change some settings to make PROFIBUS DP communication more reliable? 
YES, in the busparameters of the master you can change some settings to make the communication more reliable:
• Retries/Repeats = 5
• Tqui = 9
• MinTSDR = 22

 In HW config these options are not aviable to change. Please give some advises how change these values. And what to do more to get a stable comunication. 

Hello,
You can access the Profibus Network properties on several places.
In annex a picture wher I start from netpro, richt click on the network ==> properties.

In the Tab options you must configure how many repeaters are crossed between Master and mots far slave.
And the amount of kilometer cable between them.

This will have as effect that Step7 will compute larger response times for the slaves (needed to take into account the delays inserted by each repeater in cascade).

Compile and load HW again.

Hi!

In the Properties window choose "User-defined" instead of DP

Thank you Kahl