Chintu

Hi sudha,

You have to define plc connection for each CPU in Wincc flexible program.
e.g. Plc1 connection for MPI addr 2 of CPU1
Plc2 connection for MPI addr 4 of CPU2

Now assign Plc1 connection to all tags in Op program.
There are change connection function available in wincc flexible .
Assign this function on K3 key for CPU1
Assign this function on K4 key for CPU2.

So when you press k3 key, Your op program connect to CPU1. when you press k4 key, your op program connect to CPU2.

Regards

Chintu