Why does my Ipad Pro screen dim to black while using Face Time?

[iMore Question]

Every time I use the Face Time feature which is every day, the screen dims after a few minutes of use. How do I stop this from happening? Doesn't my Ipad know that I am in the middle of a conversation. Why is that even happening? Its almost like cutting off your phone call in the middle of the conversation. Your Ipad is saying I know your talking, but I need to save energy, so you really don't need to see each during this Face Time conversation.