Ratio on/off time formula

[Dairy]

Having a mathematical brain block this morning.

(A1)20, (B1)20, (C1)6

So A1 is the on time in minutes, B1 is the off time in minutes and C1 is the total run time in hours. I can't figure out a formula to show total run time over 6 hours which should come to 180 minutes or 3 hours. Any ideas?

 

[Dryver14]

This seems to work for me with both 20 mins and 40 mins

in D1

=C1*60/(A1+B1)*A1

 

[shg]

I don't think that works if there are not an integer number of cycles.

=A1 * INT(60*C1/(A1+B1)) + MIN(A1, 60*MOD(60*C1/(A1+B1), 1))

EDIT: Not sure that is correct either ...

 

[Dryver14]

Thanks shg

Another formula for my collection.

I'm gonna appear quite clever soon...well maybe not soon

 

[shg]

Don't save that one! This one has the added benefit being being correct (I think):

=INT(60*C1/(A1+B1))*A1 + MIN(A1, MOD(60*C1/(A1+B1), 1) * (A1+B1))

 

[Dryver14]

Ive copied over the other one this assumes that for instance if a cycle finishes with worked time at say 55mins then it just allows for 5 mins off as apposed to 25 dont change it again I'll run out of ink

 

[Dairy]

Amazing stuff can't thank you all enough.

I'll use this to help me calculate application rates for an effluent irrigator. We change the ratio in the parameters settings in the computer, depending on the weather conditions but knowing exactly what we're applying can mean a bit of head scratching.

Over application can and does result in heavy court fines and worst case imprisonment. Thanks again!