You should not be sorry. Your English is much, much better than my Hungarian. (In fact, your written English is better than at least one native English speaker who I know 
)
Do you know about the input process “Input on-time”? The description says “Counts the amount of time that an input is high in each day and logs the result to a feed. Created for counting the number of hours a solar hot water pump is on each day”.
I have never used this, but I think it will do exactly what you want - it records the duration that the input value is greater than zero, provided that the input is refreshed every 2 hours or less (which will normally be true).
