Hello: I'm having the next problem.

PC with wincc unified V20 runtime to manage a 1512SP CPU.

CPU firmware is V2.9, when same firmware version is selected in program, runtime doesn't communicate with PLC. 

Only selecting V2.8 in hardware configuration and compiling, everything runs OK. So I need to change PLC version depending if I want to load Runtime Project or work with PLC. 

I suppose problem comes from certificates, but I don't know how to fix it. Date and Time is exactly the same in PLC and Runtime machine.

Thanks

.... yes , we always switch off this option.


I've tried marking it ON and it seems it works properly. I don¡t know if this will affect to other communications where PCs are consulting data in PLC ... .  

Thanks!!!!