Machine time cycle calculation

[tmoss]

I hope someone can help me with a difficult task.
i need to calculate the hours of operation of a machine that has three different cycles.


Operational, Stand By, and Shut down.
The date and time that the machine is in each state are manually imputed.
However i would like excel to calculate the total amount of hours spent in each cycle per day.

The problem is that the cycles are completely random, and there may or may not be blank cells in between the data.