Indirtwetrust;
The cam is attached to the gal pully and picks with the car door movement. The car door should arrive at floor , open car door pick cam at same time and then sit open till it sees the hall door close contacts again. Car will not leave the floor until it sees both closed and locked contacts from the gal n interlock.

JJR :
The dpm is not used on this setup, coupling monitoring is also not used because of the manual swing hall doors.