#INVALID COLUMN

Hello Community;

I have a formula to calculate a device's time run based off the start and stopped time. This formula is applied to 10 columns (generator 1, generator 2, etc. ) and it works, however, starting in the column for generator 2 and on, l am getting the #INVALID VALUE error. Any ideas how to fix it?


Generator 2 and on is where l am stuck:

Thanks!

Answers