It is not a question of meeting my criteria but meeting the plain meaning of the NFPA requirements.
But that would work although the alarm output looks weird. As near as I can tell it has battery + connected to both sides. PAD+ and GND would do the job.
Or is this a side effect of trying to fit two schematics on a single page?
Yes, it is a compound schematic. For the controller, the Alarm connector is not used.
The alarm connector is meant for an audible buzzer that would sound, if when the Pad Disable Switch is open AND the leads are shorted AND the relay is closed, it will not provide enough current to start but will give a warning that there is a serious problem
The Pad does not use the key switch, it uses a high current switch in series between the battery supply and the REL+. When the switch is open there is no high current voltage source to the relay also no current supplied to the coil of the relay. So if the FET fails, processor fails, or relay fails, there is no battery current supplied to PAD+. The continuity circuit will supply a small sense current as well as the current supplied by the Alarm circuit if there is a fault in the hardware.
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