Because of the current drawn by the FlightDEK-D180, even very small resistances between
battery ground and instrument ground can cause voltage differences which adversely affect
engine sensor readings. An easy way to test the quality of the instrument?s ground is to measure
voltage between the ground pin at the FlightDEK-D180 and the ground lead at your aircraft?s
battery. With the FlightDEK-D180 powered on, connect one lead of your voltmeter to a free
ground lead coming from the FlightDEK-D180. Connect the other lead of your voltmeter to the
ground terminal of your battery. The voltage between these two points should measure very
close to 0 mV (within 5 mV). If it does not, you must improve the ground connection between
the ground of your battery and that of your avionics bus.