Narrow fuzzy region collecting device and method suitable for vehicle-mounted system

The invention relates to a narrow fuzzy region collecting device and method suitable for a vehicle-mounted system. The narrow fuzzy region collecting device comprises a test power module, a relay module, a comparer module and an optocoupler module; the output end of the test power module is connected to a first contact of the relay module, and a second contact of the test power module is connectedto an external input; and the output end of the relay module passes through a divider resistor and a filter capacitor and then is connected to the inverting input end of the comparer module, and theoutput end of the comparer module is connected to the input end of the optocoupler module. Compared with the prior art, the collecting precision of a collecting circuit is ensured in modes of dual threshold value setting and detecting, meanwhile the self-detection function of the collecting circuit is further additionally achieved to find a circuit failure in time, and thus the collecting circuitis detected while a narrow