Connection loss between WinCC and PLC

Hi,

I loses the connection between the PLC en WinCC sometimes. In the attachement you find the hardware setup and how i set my connection in WinCC.

I already did the following:

1. Checked all the tags for not excisting adresses (was all good)
2. Reserved  4 PG communications and 4 OP communications in hardware PLC
3. checked the connection through a continues ping command and the connection stayed very stable.
4. Checked the "status of Driver Connections" in WinnCC and there i saw the connection was disconnected sometimes.

Now point 4 was only when i called a global script (vbs and i called a script with nothing in it to be sure it was not the script) through a tag from the list of the problematic PLC. Also when i called a global script through a Cyclic Timer and know i read or write a tag from the problematic PLC the connection also got disconnected.

So i don't know what else i can look for. Anybody an idea?

Also the connection to the PLC go through a CP 343-1 Lean card. Can this be the problem maybe.

Thans in advance.Kind regards,

Ward

Hello I also have a probblem between the PLC and WinCC. So I chekced that file which you mentioned my error is following

what can I do 

Does your PLC have additional HMIs attached? This can happen if you, for example have additional TPs, and you are on the edge of the limit of the communication capabilities of the PLC.

Other thing you already checked, sometimes you put memory areas in tags, that don't exist in PLC, like DB blocks or M areas, or such.