Measuring elapsed time between two events

Hi everyone,

I want to know if in S7 300, there is a standard watch or something like that to measure the elapsed time between two events.

And if there is any, how can I determine the StartIndex value in the following function to read the elapsed time from the PLC memory?

STDMETHOD(CS7ProSim::ReadOutputImage)( long StartIndex,
long ElementsToRead,
ImageDataTypeConstants DataType,
VARIANT* pData)

Thanks in advance

I´m not familiar with S7 but with Controllogix v16 you use one of the new add on functions and you calculate elapse time.
Basically the way is done is like this: you save the start time in a register array that contains year, month,day, hour,minute,second and microsecond then you save in another register array the end time, then make a substraction and get elapsed time.
You can download the add on function from www.ab.com and try to adapt it to your S7.
Let me know if you can not download it or if you don´t have rslogix 5000 software and i can send you a pdf file with the add on function.

Good luck