[?]: WinCC and PLC s7 synch cycle

[slaven]

Hello!
I have a project WinCC 2007 flex ans S7-300.
I'm making 10 meagurments on the PLC one time per 1s and insert 10 value in DB,
after that I try to read values from wincc,
but cycle time in wincc and cycle time in PLC doesn't compare,
so from time to time I have wrong values - one value on two cycle but the true value Ive lost.
The question is - how can I sychronize time between Wincc and PLC?

Thanks beforehand.