Electronics International FL-2 User Manual

Page 11

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Selecting the Proper Filter:

The filter may be programmed for a response time of 8, 16, 32, 64 or 128 seconds (time to 100% respond to

a change in the fuel level). The advantage and disadvantage of a fast and slow filter setting is discussed below.

Advantages of a faster filter setting (8 to 16 seconds) - A fast response time may show some fluctuations in

the fuel level during sloshing or turns. This can give you a good feeling the instrument is working, and there is
fuel in the tank. If you ever fly with low fuel levels, this can be very comforting. Once you reach level flight and
the fuel has leveled out, accurate fuel levels will be displayed in 8 to 16 seconds depending on the filter setting.

Disadvantages of a faster filter setting (8 to 16 seconds) - A fast response time could show excessive fluctua-

tion in the fuel level that could be annoying. This is especially true for thin wet long wing tanks with little dihe-
dral. Fluctuation can cause the FL-2 to read from near empty to near full.

Advantages of a slower filter setting (32 to 128 seconds): - A slower filter can stabilize the display and

remove all short term fluctuations.

Disadvantages of a slower filter setting (32 to 128 seconds): - If you stay in a turn for a long period of time,

aircraft with thin wet long wings tanks and little dihedral can have a significant shift in fuel. Eventually this will
effect the fuel level readings. Once you establish level flight and the fuel has leveled out, it will take 32 to 128
seconds for an accurate fuel level reading to be displayed on the FL-2, depending on the filter setting.

How your aircraft will react to different filter settings depends on your tanks shape, size, baffles, baffle hole

sizes, and probe placement. You may need to experiment with the filter setting to get the results you like best.
The filter setting has no effect on calibration or the response time during calibration.

Selecting the Proper Operating Mode:

If you have an FL-2CA Instrument (used with and Electronics International capacitive probe) set the operat-

ing mode to “FL C” the “FLrH” mode will cause the instrument to read improperly.

If you have an FL-2RA-12 or -24 and a resistive fuel probe that decrease

decrease

decrease resistance as you add fuel, set the

operation mode to “FL r”.

If you have an FL-2RA-12 or -24 and a resistive fuel probe that increase

increase

increase resistance as you add fuel, set the

operation mode to “FLrH”.

Selecting the Resolution:

The units of measure (gallons, liters, lbs.) the FL-2 is calibrated in, will be the units of measure the FL-2 will

display fuel levels in during operation. If the FL-2 is to be calibrated in gallons, the resolution of the digital
display may be set for one gallon (shown as “GAL1”) or ½ gallon (shown as “GAL.5”). If you calibrate the FL-2
in liters, pounds or any other units, the resolution should be set to “GAL1”.

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