"6) Auxiliary Input to control/ trigger when or how a unit can regenerate based on the setting of the dP screen in the programming setup. External inputs should be dry contacts and units wired in parallel require matching each unit’s polarity. Labeled AUX INPUT."

http://www.vibranth2o.com/images/Cla...rogramming.pdf

ИМХО "dry contacts" указаны однозначно.