Hi,

I have a project to install data logging onto an existing system. The logging PC will be located in the office far from the machine. To connect the CPU314 with the office based PC I have installed a CP343-1 Lean module to communicate over Ethernet.

The machine has an OP277 panel connected via MPI. When the CP343-1 Lean module is installed it will not connect to the CPU314. After a month or so of site visits, I discovered that if I switched off the termination on the MPI cable connecting to the OP277 panel, the CP343-1 Lean module, would kick into life and I would have comms between all modules and office based PC. Unfortunately this has seemed to introduce a fault where the OP277 panel will intermittently drop connection and the machine has to be power cycled for the panel to reconnect.

When investigating the signals on the MPI bus, I can see nice clean data with termination on and with termination off I can see reflections. When termination is on, I lose all Ethernet coms on CP343-1 Lean module and switch it off comms returns immediately.

Any help suggestions are welcome, thanks.

Hello,

hmmm some old idea going through my head, maybe I'm wrong but look to CP343 in HW cfg if there's some info about MPI/DP address occupation/connection, simply check this if some violation of parameters to other CPU is located. I don't understand why Ethernet CP343 card can interference MPI/DP network, had never this problem.

hi,

what CPU do you have exactly?

I know that smaller CPU´s, 312 - 315-2DP, the communication-bus(K-bus) is performed as "party-line", that means it is physically connected to MPI-interface. 

Check if the CP343-1 lean has assinged a MPI-adress. Maybe it is the same like your panel has.

hope this helps,

regards,

Hi, thanks for the response.

I on the MPI bus I have:

CPU314 - MPI 2

OP277 - MPI 3

CP343-1 Lean - 31

The last address for the CP343, was set to ensure there was no conflicts, I have set up that that is the highest allowed connection. The problems were there when I had the MPI 4 for the CP343 too. The hardware configuration for the module to the best of my ability seems to be correct.

the PLC is

CPU 314

6ES7 314-1AG14-0AB0 FW: 3.0

Hello,

pls make test with finding nodes on your MPI network, you have chioce how to make it. One way is via PG/PC interface, maybe some parameters are missing, violating, maybe exists other node in higher range of address.