Teltonika FMA110 User Manual page 19

Fuel Tank sensors
A fuel tank level sensor exists in most cars, which shows the
approximate fuel level in the driver's indicator panel. It is possible
to connect FMA110 Analog input to it (if sensor returns analogue
signal proportional to fuel level). Figure 10 shows the connection
scheme to the FMA110 and fuel tank sensor. After the connection
to the tank fuel level sensor, calibration is needed. Calibration is
needed because most fuel tank sensors are not linear. Calibration is
performed by measuring voltage dependence on volume of fuel in
tank.
Alarm buttons, door sensors, etc.
Alarm buttons, door sensors, ignition, etc. return two states: high or low voltage. Digital
inputs are used to read this information. Figure below shows how to connect alarm button, door
sensor, etc.
In cases when sensor output signal is negative, an additional relay has to be installed to
convert negative signal to positive.
Figure 11 Panic button connection
Figure 12 Inverting relay connection
Figure 10 Fuel sensor scheme
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