MPI Network

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Thread Starter

Adrian Hernandez

I´m making an MPI network with over 30 nodes, about 14 PLC siemens S7-300, several touchpanel, op´s and interbus interface card modules.

Everthing work very well, but there are 4 nodes, that are the final ones in my bus, when I connect this four nodes, suddenly I lose global
communication between 3 other nodes, and I dont know why. I´m using repeaters to extend the distance of my network, because there are three
sections where I have all the nodes, and there´s about 100 mt between them.

I mean I have 12 nodes then a repeater,100 mt distance, then another repeater, then about 14 nodes then a repeater, 100 mt distance, then
another repeater then 4 nodes, this final ones are the ones that make this not to work properly.

Do you know what is possibly causing this lost of communication.
 
Z

Zan Von Flue

hi
I don't know the answer but I found acouple of websites in siemens that may
help

http://www4.ad.siemens.de/csinfo/livelink.exe/fetch/299151/mpikom_e.pdfAND
http://www4.ad.siemens.de/csinfo/livelink.exe?lang=en&func=cslib.csinfo2&content=%2Fskm%2Fsearch.asp%3F&Query=global+data
AND
https://mall.ad.siemens.com/DE/guest/index.asp?aktPrim=0&lang=en&nodeID=5000053&foldersopen=-990-872-668-667-666-1-901-906-917-&jumpto=917

For the 300 series Siemens says max. 16 CPU's.
Are they adressed correctly?
Happy hunting
zan
 
H

Hakan Ozevin

The only possibility I can imagine is the terminating resistors on the last repeater. Are they correctly adjusted?

 
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