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venerdì 3 aprile 2015

Avionics bending: Fuel quantity indicator

The fuel quantity indicator shows these informations:

-Left fuel quantity
-Right fuel quantity
-Center fuel quantity
-Total fuel quantity
-Fuel Temperature

The indicator's display has a high contrasr, dual-cell liquid Crystal display set out from the indicator bezer for increased visibility and viewing angle.
The indicator has 4 separate circuits, one for each tank display to make sure that a failure in one of them won't affect the others.

The 3 fuel tank quanityt displays have a resolution of 0.1 and a max value of 99.9.
The total fuel quantity display has a resolution of 0.1 and a max value of 999.9.
Fuel quantity shows to a resolution of 100lbs/kgs (lbs or kgs selectable by a program pin)

The indicator receives fuel quantity information over one of two ARINC 429 digital data buses, A or B.
Bus A is normally used and is selected at start-up or after a circuit test is complete. If bus A information becomes unavailable, the indicator keeps bus A data and after 4 seconds changes to bus B.
If it doesn't receive data on bus B after 4 seconds, the receiver continues to cycle at a 4-second rate until valid data is recognized.
If both buses are inactive, the tank indicator(s) show letters -Ab to show a dual bus failure.

Here is a video of gauge power up with no ARINC data provided yet.

 
And this video shows startup with no ARINC data, then the unit is feeded with fuel quantity data per tank