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Figure 9 Digital key “I-Button” DS1990A connection scheme
Fuel tank sensors
A fuel tank level sensor exists in most of the cars, which shows the approximate fuel level
in the driver’s indicator panel. It is possible to connect FMB630 Analog input (if sensor returns
analogue signal proportional to fuel level). Figure 10 describes the connection scheme to the
FMB630 and fuel tank sensor. After the connection to the tank fuel level sensor, calibration is
needed. Calibrations needed due of the fact that most fuel tank sensors are not linear.
Calibration is being performing by measuring voltage dependence on volume of fuel in tank.
Figure 10 Fuel tank sensor
