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Siemens S7 412-1 can't go online
Cannot go online to Siemens S7 412-1 CPU

Hi All

I have a problem with my Siemens S7 PLC
I can't seem to go online to it. The message given is 'no other active partner found'.

There's a pro-face HMI connected to the PLC via its MPI port. There was an error on the CPU: The EXTF & BUS1F LEDs were lit.
In order to make these LED's ok I restarted the PLC, and the LEDs were ok then.

But then I could no longer go online with my laptop even though I have not made any changes to the configuration!

any suggestions?

Safety Guy

just an update:

I have tried to re-download the program on the CPU but there is still the same error (NO OTHER ACTIVE PARTNER FOUND)

By Gabriele Corrieri on 11 February, 2012 - 3:55 pm


try disconnect any MPI nodes physically on network, just plug an MPI cable from you to CPU, remove any memory cards from CPU, and retry. start from available nodes on network.

Bit suggestions: I'm sure that you're skilled on, but check that the S7 Online point over (MPI) and the MPI port or adapter is healthy, try go online on other CPU.

My opinion was in a corrupted content of memory card due to a failure, power loss or any other cause.


got once a similar problem with an S7-300 CPU.
The PLC was reset after inserting a new MMC.

I was using a CP5512 and there was no way to go online nor having any MPI node listed in "accessible nodes" window in S7 Manager until I switched on the "PG/PC is the only master on the bus" option in "set PG-PC interface".