MPI Network


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.

Zan Von Flue

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

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

Hakan Ozevin

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