From den4b Wiki
You can set any of the following relationships between the events:
- ALL - All events must be in triggered state together, monitored continuously.(This is the default choice)
- AND - Every event must be triggered once, independently of each other.
- OR - Any event must be triggered once.
- 1BY1 - Each event must be triggered once, one after another.
If you are not sure which logic to choose, simply use the default "ALL" logic which normally satisfies most scenarios.