Dry Node Definition: A dry node is a passive switch with two states: open and closed. There is no polarity between the two nodes, and they are interchangeable. Examples include buttons, rotary switches, relay outputs, etc.
Wet Node Definition: A wet node is an active switch with two states: energized and de-energized. The polarity between the two contacts is reversible. A wet node can be understood as a signal with a voltage difference, usually with polarity and not interchangeable.