Shadin Digiflo-L User manual

Digiflo-L
Digital Fuel
Management System
RS-232 and RS-422 output format
with interface to LORAN-C and GPS receivers
OPERATING MANUAL
Single and Twin Engine Indicators
For P/N: 91053XP
Shadin Co., Inc.

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TABLE OF CONTENTS
1. GENERAL DESCRIPTION.....................................................3
1.1 THE SYSTEM PROVIDES ..................................................................................4
1.1.1 SPECIFIC RANGE.................................................................................4
1.1.2 FUEL TO DESTINATION...................................................................4
1.1.3 FUEL RESERVE....................................................................................4
1.1.4 ENDURANCE.........................................................................................4
1.1.5 FUEL FLOW ...........................................................................................5
1.1.6 FUEL USED............................................................................................5
1.1.7 FUEL REMAINING..............................................................................5
1.2 SYSTEM COMPONENTS....................................................................................6
1.2.1 FUEL FLOW TRANSDUCER............................................................6
1.2.2 LORAN-C OR GPS RECEIVER.........................................................6
1.2.3 PANEL MOUNTED UNIT...................................................................6
1.3 TEST FUNCTION...................................................................................................7
2. PREFLIGHT PROCEDURES.................................................8
2.1 INITIAL PROGRAMMING.................................................................................8
2.2 PREFLIGHT CHECK............................................................................................9
2.3 NO FUEL ADDED .................................................................................................10
2.4 FUEL TANKS FULL.............................................................................................10
2.5 PARTIAL FUEL ADDED ....................................................................................11
2.6 CORRECTING FUEL ON BOARD ENTRY ERROR................................12
3. INFLIGHT OPERATIONS....................................................13
3.1 INSTRUMENT OPERATION...........................................................................13
3.1.1 FUEL FLOW .........................................................................................13
3.1.2 FUEL USED..........................................................................................13
3.1.3 FUEL REMAINING............................................................................13
3.1.4 ENDURANCE.......................................................................................13
3.1.5 NAUTICAL MILES PER GALLON ................................................13

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3.1.6 FUEL TO DESTINATION.................................................................13
3.1.7 FUEL RESERVE..................................................................................14
3.2 WARNINGS ............................................................................................................15
3.2.1 NOT ENOUGH FUEL.........................................................................15
3.2.2 RESERVE FUEL WILL BE USED ..................................................15
3.2.3 LOW ENDURANCE...........................................................................15
3.2.4 LOW FUEL REMAINING.................................................................15
4. EMERGENCY PROCEDURES...........................................16
5. ERROR MESSAGES............................................................16
6. CONFIGURATION DATA ENTRY.....................................17
7. SPECIFICATIONS ................................................................23
8. WARRANTY INFORMATION .............................................25
NOTE: Though references are made in this manual to fuel measured
in gallons, the information applies equally to measurements in
pounds, kilos, or liters.

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Digiflo-L
Although not required by the FAA, it is recommended that this
manual be attached to the FAA-approved Flight Manual, or always
kept on board for reference.
1. GENERAL DESCRIPTION
Digiflo-L is a Digital Fuel Management System designed to provide
complete fuel management information under real flight conditions
without any manual entry of data (after entry of the initial fuel on
board information).
Digiflo-L is connected to the engine fuel flow transducer for fuel
flow information and to the Loran-C or GPS receiver serial port for
navigation data (ground speed, distance and estimated time en
route).
This system is also capable of transmitting the fuel information to
the Bendix/King KLN-88, KLN-90, and Garmin GPS navigation
receivers, for additional calculations and display of fuel
management data.
Digiflo-L is set up to measure the flow of fuel in either gallons,
liters, or pounds, and it can be installed on virtually any
reciprocating or turbine engine by selecting the proper size fuel
flow transducer.

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1.1 THE SYSTEM PROVIDES
1.1.1 SPECIFIC RANGE
Specific Range (NM/GAL) = Ground Speed (Kt.)/Fuel Flow
per hour. This is an indication of how efficient the cruise is
and the optimum cruise speed can be determined by
selecting the power setting, which yields the highest
NM/GAL, NM/10LB, or NM/5LIT of fuel burned.
1.1.2 FUEL TO DESTINATION
Digiflo-L calculates (under real wind conditions) the fuel
necessary to reach the destination as selected on the Loran-C
or GPS receiver by multiplying the fuel flow by the
estimated time en route to the destination. (If an
intermediate waypoint is selected for navigation purposes,
the displayed fuel to destination represents the fuel needed
to reach the intermediate waypoint unless the distance to the
destination is in the serial message.)
1.1.3 FUEL RESERVE
Digiflo-L calculates the amount of fuel, which will be
available on board when the aircraft reaches the destination
or waypoint indicated on the Loran-C or GPS receiver. This
feature provides the pilot with accurate information so that
the reserve fuel situation can be evaluated and action can be
taken if necessary. (If an intermediate waypoint is selected
for navigation purposes, the displayed fuel reserve
represents the fuel reserve at the intermediate waypoint
unless the distance to the destination is in the serial
message.) Fuel Reserve = Fuel Remaining –Fuel to Reach
Destination.
1.1.4 ENDURANCE
Digiflo-L calculates the time left to fly in hours and minutes
based on the fuel remaining and the present fuel flow.

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1.1.5 FUEL FLOW
The system provides a digital readout of the fuel per hour to
a tenth of a gallon up to 100 gallons and to the nearest
gallon above 100 gallons. For the pounds version, the
readout is to the nearest pound up to 999 lbs./hour and to the
nearest 10 lbs. above 999 lbs./hour.
1.1.6 FUEL USED
The system keeps track of the fuel used since the last fuel
entry or reset.
1.1.7 FUEL REMAINING
The system keeps track of the fuel remaining on board. Fuel
Remaining is equal to Initial Starting Fuel minus Fuel Used.

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1.2 SYSTEM COMPONENTS
The system consists of three (3) basic units: the fuel flow
transducer, the navigation receiver (Loran-C or GPS) and the panel
mounted unit.
1.2.1 FUEL FLOW TRANSDUCER
The fuel flow transducer mounted in the fuel line measures
the flow of fuel and generates electrical pulses directly
proportional to the fuel flow. The transducer is fail-safe
designed, and stopped rotor will not interrupt fuel flow to
the engine.
1.2.2 LORAN-C OR GPS RECEIVER
The Loran-C or GPS receiver provides ground speed,
distance, and estimated time en route through the serial port.
1.2.3 PANEL MOUNTED UNIT
All system electronics, function controls, and digital
displays are contained in a single instrument that mounts in
a standard 3 1/8” dia x 6.5” Deep opening. This unit
requires no periodic maintenance, adjustment, or calibration
once it is properly installed.
The Display: The fuel flow is always displayed on the lower
windows. All other functions, with the priority for the rotary switch
functions, are displayed on the upper window.
System Memory: The system includes a non-volatile memory that
retains fuel remaining and fuel used information when the power to
the unit is shut down.

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1.3 TEST FUNCTION
Diagnostic software is built into the system. To activate it, press
the TEST/ENTER button and hold until “8’s” begin to appear
across the display windows and then release. If the test is
successful, the word “Good” will appear on the upper display
window for three seconds. If the test is not successful, the word
“bAd” and an error message identifying the error will be displayed.
In such case, the unit will cease to function and must be considered
unserviceable until corrective action is taken.
At the end of the test routine the system will display the following:
1. In the twin engine models the left lower window displays
the K-factor for the left engine, and the right lower window
displays the K-factor for the right engine. The next screen
displays the right engine K-factor again. This number must
match the pulse count stamped on the fuel flow transducer
otherwise all the readout will be inaccurate. The units (Gal,
LB5.8, LB6.7, etc) display in the upper window.
2. The distance to waypoint or destination is displayed on the
upper window as shown on the Loran-C or GPS receiver to
check the Data Interface Integrity (not available without
signal).
If the system is not capable of reading the navigational
receiver data, the word “LbAd” will be displayed on the
upper window. If the Loran-C or GPS receiver is turned off,
the display shows “LoFF”. The lower left window displays
the Loran-C or GPS type.
3. “FUL” appears in the lower left window and the maximum
usable fuel in the upper window.
4. Software version and revision level in the lower windows.
Note: Using the test function while engines are running will cause
the computer to lose 17 seconds of fuel count.

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2. PREFLIGHT PROCEDURES
Digiflo-L is a fuel flow measuring system and NOT a quantity-
sensing device. A visual inspection and positive determination of
the usable fuel in the fuel tanks is a necessity. Therefore, it is
imperative that the determined available usable fuel be manually
entered into the system.
2.1. INITIAL PROGRAMMING
The function of initial programming is to enter the total usable fuel
into the memory. It can then be recalled whenever the fuel tanks
are filled up to the maximum usable fuel. The “FUL” fuel setting
determines the maximum amount of fuel that can be entered by any
method into the Digiflo-L.
PROCEDURE:
1. Power the unit up.
2. Move the FULL/ADD toggle switch to the FULL position
and hold for the entire procedure.
3. Press and hold both the REM and USED buttons,
simultaneously. The system will then countdown for 15
seconds, displaying the count on the left display window.
4. The word “FUL” appears in the lower display window, and
the current full fuel value appears in the upper display.
Release the REM and USED buttons. Keep holding the
FULL/ADD toggle switch in the FULL position.
5. Use the REM button to increment the full fuel number or the
USEDbutton to decrement the full fuel number. (The
longer you hold the button, the faster the number will be
updated.)

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6. After reaching the correct total usable fuel figure, press the
TEST/ENTER button and the computer will store that
number as full fuel. The word “FUL” disappears and the
computer will return to the operating mode. Release the
FULL/ADD toggle switch.
7. To verify that the data is stored properly, press the
TEST/ENTER button. The computer will run a diagnostic
check and then display “Good”. If the test is successful, it
will display the maximum usable fuel.
NOTE: Do not turn the power off to the computer for
approximately one minute. This will ensure that the unit has
enough time to store the proper figures into the program.
2.2 PREFLIGHT CHECK
Diagnostic software is built into the system. To activate it, press
the TEST/ENTER button and hold until “8’s” begin to appear
across the displays windows and then release. If the test is
successful, the word “Good” will appear on the upper display
window for three seconds. If the test is not successful, the word
“bAd” and an error message identifying the error will be displayed.
In such case, the unit will cease to function and must be considered
unserviceable until corrective action is taken.
At the end of the test routine the system will display the following:
1. In the twin engine models the left lower window displays
the K-factor for the left engine, and the right lower window
displays the K-factor for the right engine. The next screen
displays the right engine K-factor again. This number must
match the pulse count stamped on the fuel flow transducer
otherwise all the readout will be inaccurate. The units (Gal,
LB5.8, LB6.7, etc) display in the upper window.
2. The distance to waypoint or destination is displayed on the
upper window as shown on the Loran-C or GPS receiver to

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check the Data Interface Integrity (not available without
signal).
If the system is not capable of reading the navigational
receiver data, the word “LbAd” will be displayed on the
upper window. If the Loran-C or GPS receiver is turned off,
the display shows “LoFF”. The lower left window displays
the Loran-C or GPS type.
3. “FUL” appears in the lower left window and the maximum
usable fuel in the upper window.
4. Software version and revision level in the lower windows.
Press the USED button, and the system will display the fuel used
since last fuel entry or fuel used since last reset.
Press the REM button, and the system will display the fuel
remaining on board. The pilot should confirm this figure with the
actual fuel on board.
2.3 NO FUEL ADDED
This automatically stores information concerning previous fuel
levels, even in the case of a power down. If no fuel is added, no
action is needed in updating fuel data.
2.4 FUEL TANKS FULL
There are two methods to enter full fuel: the ramping method and
the FULL/ADD toggle switch method.
Ramping Method
•Press the REM button and hold.
•Press the TEST/ENTER button to increment the fuel remaining
until the total usable fuel is reached. (The longer you press, the
faster the incrementing.)

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•Release the REM button and the TEST/ENTER button to enter
the total usable fuel on board into memory.
•If the required figure is exceeded, follow the procedure in this
manual, section 2.6 Correcting Fuel on Board Entry Error.
FULL/ADD Toggle Switch Method
•Move the FULL/ADD toggle switch to the FULL position and
hold.
•Press the TEST/ENTER button.
•Release the FULL/ADD toggle switch so it returns to the center
position.
•To verify, press the REM button. The total usable fuel will be
displayed on the upper window.
2.5 PARTIAL FUEL ADDED
There are two methods to enter partial fuel:
Ramping Method
Add the amount of fuel from the refueling meter to the amount of
fuel remaining. Enter the total using the following steps:
•Press the REM button and hold.
•Press and hold TEST/ENTER button to increment fuel
remaining until figure to be entered is reached; then release
button.
•Release the REM button. The displayed figure is entered into
memory as fuel remaining on board.
•If the required figure is exceeded, follow the procedure in this
manual, section 2.6 Correcting Fuel on Board Entry Error.
FULL/ADD Toggle Switch Method
•Move the FULL/ADD toggle switch to the ADD position and
hold.
•Press the REM button to increment the fuel added figure until
the amount of fuel added is reached.
•Press the TEST/ENTER button.

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•Release the FULL/ADD toggle switch so it returns to the center
position. The computer will add the added fuel remaining and
use the total as the current fuel remaining.
•To verify, press the REM button. The current usable fuel
remaining will be displayed on the upper window.
2.6 CORRECTING FUEL ON BOARD ENTRY ERROR
In case an error has been made by exceeding the correct amount in
entering the total usable fuel, press and hold the USED button, and
simultaneously press and hold TEST/ENTER button. The fuel
remaining figure will appear and pause in the display window for
four (4) seconds. The figure will decrement (the longer you press,
the faster it decrements). When the correct figure is reached,
release both the USED and the TEST/ENTER buttons. To avoid
repeating the four-second pause before decrementing, hold the
USED button, and use the TEST/ENTER button to control the
decrementing.
Note: Adding or subtracting fuel by any method resets the fuel used
value to zero.

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3. INFLIGHT OPERATIONS
3.1 INSTRUMENT OPERATION
3.1.1 FUEL FLOW
Fuel Flow is displayed continuously on the lower display
windows.
3.1.2 FUEL USED
Fuel used is displayed by pressing the USED button. The
information is shown on the upper display window as long
as the button is held in the USED position. The display
represents the fuel used since last reset.
3.1.3 FUEL REMAINING
Fuel remaining is displayed by pressing the REM button.
The information is shown on the upper display window as
long as the button is held in the REM position. The display
represents the fuel remaining on board at the time of
reading.
3.1.4 ENDURANCE
Endurance is selected by rotating the rotary switch to the
ENDURANCE position. Endurance is displayed in hours
and minutes on the upper display window.
3.1.5 NAUTICAL MILES PER GALLON
Nautical miles per gallon is selected by rotating the rotary
switch to the NM/GAL position. The information is shown
on the upper display window.
3.1.6 FUEL TO DESTINATION
Fuel to destination is selected by rotating the rotary switch
to the FUEL TO DESTINATION position. The information
is shown on the upper display window and represents the
fuel needed to reach either the active waypoint selected on
the Loran-C (or GPS receiver) or the final destination (if the

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total distance record is provided in the serial message.) This
assumes the aircraft ground speed and fuel flow remains
constant and the aircraft remains on flight plan course.
(Readings obtained during climb and descent are invalid.)
3.1.7 FUEL RESERVE
Fuel reserve is selected by rotating the rotary switch to the
FUEL RESERVE position. The information is shown on
the upper display window and represents the fuel that will
be available when the aircraft reaches its destination as
indicated on either the selected waypoint or the final
destination (if the total distance record is provided in the
serial message.) This assumes the aircraft ground speed,
altitude, fuel flow, and direction remain constant. (Readings
obtained during climb and descent are invalid.)

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3.2 WARNINGS
3.2.1 NOT ENOUGH FUEL
When the rotary switch is in FUEL TO DESTINATION
position, the information in the display window flashes if
fuel on board is insufficient to reach either the destination
selected as the active waypoint or the final destination (if
that total distance record is provided in the serial message).
Display window shows amount of fuel short to reach
destination preceded by a negative sign.
3.2.2 RESERVE FUEL WILL BE USED
With the rotary switch in the FUEL RESERVE position, the
information in the display window flashes if the aircraft will
arrive at the destination with less than the pre-programmed
Endurance Warning Time minutes of fuel –calculated at the
present cruise power setting. This warning is intended to
alert the pilot that the prevailing condition will require the
use of some of the selected reserve fuel to reach the
destination.
3.2.3 LOW ENDURANCE
The Digiflo-L can be configured to display a warning based
on the time remaining to fly. When the rotary switch is in
the ENDURANCE position, and the actual endurance is less
than the pre-programmed Endurance Warning Time, the
data in the right half of the display flashes. Press the
TEST/ENTER button to acknowledge the warning. (Note:
Resetting the Digiflo-L or adding fuel resets this condition
and the warning is enabled again).
3.2.4 LOW FUEL REMAINING
The system displays “Lo FUEL” when the fuel remaining
reaches the pre-programmed Low Fuel Level configured in
setup. Fuel flow information will not be displayed again
until the pilot acknowledges this message by pressing the
TEST/ENTER button. Fuel calculations are not interrupted
by this message. (Note: Resetting the Digiflo-L or adding
fuel resets this condition and the warning is enabled again).

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4. EMERGENCY PROCEDURES
In case of electrical power failure in-flight, the instrument will
cease to function. After restoring power, the system will resume
accurate fuel flow reading, but time remaining, fuel used, fuel
remaining, fuel reserve, fuel to destination and all warnings will not
be accurate unless the duration of power failure is known and fuel
consumption during the electric power failure is calculated and
subtracted from fuel remaining.
5. ERROR MESSAGES
ERROR 1:
Due to the necessity of Group 1 settings, if the Flow Meter is set to
Operate Mode and the checksum of Group 1 is bad, the display will
flash: E1.
This refers to Error 1, Group 1. The flow meter will not continue to
function after this point, and will continue flashing E1, alerting that
the flow meter must be serviced.
ERROR 2:
The Flow Meter will still be accurate and operate under NON-
LORAN pages, if the checksum of Group 2 is bad. In this case,
under any Loran page, the Loran information will be replaced by
E2.
This display refers to Error 2, or Group 2. This is to alert the pilot
that the Flow Meter does not have valid Loran and Output
selections, and therefore, can not rely on Loran and Output
information.
NOTE: Remember it is possible to set group settings without
having to be in entry mode; therefore, this error can be fixed by
going into Manual Entry Mode.

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6. CONFIGURATION DATA ENTRY
Manual Entry Mode
Ordinarily, the fuel flow indicator has been set up by the factory to
match the K-factor of the supplied transducers and other set-up
information. However, there are built-in provisions to change the
set-up. Please be sure to define and document initial set-up before
attempting to make changes.
Overview
Previously, all settings depended upon the switches mounted on the
processor board. Currently, the Digiflo-L processor board and
software version 60.10.XX has a feature that is referred to as
Manual Entry Mode. In this mode, the Flow Meter settings are
stored as two groups: Group 1 and Group 2.
Manual Entry Mode can be accessed in two ways: one providing
access to both Group 1 and Group 2 values, and one providing
access to only Group 2 values. The access to Group 2 values can be
obtained while the unit is installed in the aircraft. Access to Group
1, however, requires removal of the unit to adjust switch settings.
Group 1: Generally, Group 1is set up by the distributor and
contains information defined by the part number. However,
although functions are defined here, do not change them without
proper knowledge or they will affect performance of the indicator.
Group 2: Group 2 must be set up by programming the unit in
Manual Entry Mode. Group 2 settings allow the user or installer to
change Loran or GPS input and output parameters, endurance
warning time, and fuel flow filtering types.

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Locations of the switches for the Digiflo-L are as follows:
Display Side
Each switch has 16 positions, 0-9, A, B, C, D, E, and F.
Note: A hole has been cut into the can to allow access to switches
normally covered by the red K-factor sticker.
Operation Mode vs. Entry Mode
FE: If Switch 1 is set to F and Switch 2 is set to E, the unit is in
Entry Mode. This is the only mode that will allow the
setting of Group 1 values onto the non-volatile memory of
the unit. In this mode, both groups can be set. Once
installed in the aircraft, this mode is no longer accessible.
FF: Once the settings have been programmed, Switches 1 and 2
should be set to FF. This is the Operation Mode, which is
required for normal operations. In this mode, settings
previously recorded for Groups 1 and 2 will be utilized, and
not the switches. Group 2 can still be accessed through the
Manual Entry Mode, but Group 1 is not accessible.
Switch Entry Mode Operation Mode
1 FF
2 EF
3 0 0
4 0 0
SW2 SW1

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Manual Entry Mode
There are two ways to access the Manual Entry Page.
1. Set Switches 1 and 2 to Entry Mode and power up. This
allows access to both groups.
2. If the Switches are not set to Entry Mode, while running
under normal conditions, press the TEST/ENTER button to
start the test mode. When the version is displayed, press and
hold the TEST/ENTER button for 15 seconds. This allows
access to Group 2 only.
In both instances, “ENT” will be displayed.
The display can now be paged through using the fuel “USED”
button to scroll forward or the fuel REM button to scroll back.
REM
USED
*L
*R
*A
*B(b)
*U
*E
*C
O
I
D(d)
F
W( )
S
u
VALUES
DISPLAYED