I have designed my own EVSE but am having trouble finding a precise description of how the EV proximity detection actually works. Does anyone know what the J1772 spec or specifically the Nissan Leaf is looking for on the "proximity" pin to decide the connector is engaged. I've looked around and all the descriptions are vague and don't provide a description, block diagram or schematic as with the pilot signal. The pilot signal is well described but most sources simply state the proximity pin is used by the EV to know the connector is engaged but without details.
My J1772 cable/connector provides a wire for the proximity pin but I've been unable to find anything that explains what the EVSE provides on this signal pin. Can anyone provide me with either an explanation of what the EVSE must provide on the proximity pin?
Is it grounded?
Does it have a specific resistance to ground?
Is it related to the EVSE/EV states/pilot sequence?
Is it connected in any way to the connector engagement button?
My cable/connector has a direct connect from the proximity pin to the wire and the button has no effect on it.