Filser Electronic GmbH
SmartTrim Xn
Pleas check at www.Filser.de for the last version !
Version “ K /L” Sep/29/2006
Active trimming
SmartTrim X1+X2
(Autopilot)
133
HEADING
For refitting and basic installation of small aircrafts
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Filser Electronic GmbH
SmartTrim Xn
1
Operation............................................................................................................. 4
1.1
General: ....................................................................................................... 4
1.2
Display and handling .................................................................................... 4
1.2.1
Definitions (Heading / Track)................................................................. 4
1.2.2
Control functions ................................................................................... 5
1.2.3
Second line ........................................................................................... 5
1.2.4
Heading pre selection : ......................................................................... 5
1.2.5
Background information ........................................................................ 6
1.2.6
Examples: ............................................................................................. 6
1.3
Summary of control functions: ...................................................................... 7
1.4
How to use ................................................................................................... 7
1.4.1
Disable (DIS)......................................................................................... 7
1.4.2
Roll-Drift ................................................................................................ 8
1.4.3
Horizontal reference.............................................................................. 8
1.4.3.1
Pitch-Setup .................................................................................... 8
1.4.3.2
Pitch display................................................................................... 8
1.4.4
HOLD for X2 (hold altitude) ................................................................... 8
1.4.5
Quality of altitude control....................................................................... 9
1.5
Coupling. .................................................................................................... 10
1.5.1
General information............................................................................. 10
1.5.2
Handling .............................................................................................. 10
2 Installation ......................................................................................................... 11
2.1
Mechanical installation ............................................................................... 11
2.1.1
Type of servo drive:............................................................................. 11
2.1.2
Easy installation of the servo to the aileron: ........................................ 11
2.1.1.1 Check of the spring tension................................................................ 12
2.1.3
Installation of the double servo mechanism to the aileron:.................. 12
2.1.4
Control of the elevator (X2 only).......................................................... 13
2.2
Wiring ......................................................................................................... 14
2.2.1
General ............................................................................................... 14
2.2.2
Wiring for the vertical axis (X2 only):................................................... 14
2.2.2.1
Test .............................................................................................. 14
2.2.3
GPS source......................................................................................... 14
2.3
Attitude of the SmartTrim instrument.......................................................... 15
2.4
First time set up.......................................................................................... 16
2.4.1
Set up of the roll axis........................................................................... 16
2.4.1.1
Rolldrift-Setup .............................................................................. 17
2.4.2
Set up of the pitch axis (X2 only)......................................................... 17
2.4.2.1
Adapting the pitch trim ................................................................. 17
2.4.2.2
Pitch-Setup .................................................................................. 18
2.4.2.3
Calibration of control factors F(Pitch- tolerance- window) and
G(Pitch-trim period)........................................................................................ 18
2.5
Behaviour of X2 without GPS-Data ............................................................ 18
2.6
Overview parameter setting ...................................................................... 19
2.6.1
Commands.......................................................................................... 19
2.6.2
Aircraft characteristic parameters........................................................ 19
2.6.2.1
Roll axis until version X1B............................................................ 19
2.6.2.2
Roll axis for version X1/2C and later ............................................ 19
2.6.2.3
Elevation axis (X2 only)................................................................ 20
2.7
Special hints ............................................................................................... 21
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Filser Electronic GmbH
SmartTrim Xn
3
Technical data: .................................................................................................. 22
3.1.1
Overview ............................................................................................. 22
3.1.2
Data .................................................................................................... 22
3.1.3
Connector pinning: .............................................................................. 22
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Filser Electronic GmbH
SmartTrim Xn
1 Operation
1.1 General:
The goal of the SmartTrim X1/X2 is, similar as an usual auto pilot, to make the Wing
Leveling and bring the airplane into the required direction, but using a force as small
as possible to the aircraft control.
Therefore soft springs are used to bring the force from the servo to the control
mechanism. To control the altitude, the original pitch trim of the aircraft will be used.
1.2 Display and handling
After turn on by pressing the button RELEASE (ON/OFF) at the left top, the
SmartTrim starts operation. The mode A+H (= Altitude & Heading) for the type X2
and HDG (Heading only) for the type X1 will be set automatically.
To turn off again, press the button RELEASE for a long time (more than 3 seconds).
On both types the DIS (Disable) status is set after turn on. This status or the
operation mode will be displayed in the top left position of the first line.
After initialization the display shows:
config.
status
DIS HDG
- - - x000
GPS-course
selected course
flag
Status: Status of SmartTrim:
DIS = disable (for mode HDG, H+A, WL)
HDG= hold heading
H+A = hold heading and altitude (X2)
WL = wing levelling only,
lower line displays required bank +/8max. (8 = app. 30° bank)
Config: for HDG gyro drift (<n>)
for WL required bank (<n>)
for H+A .......................
GPS-course: the real ground course coming from
an external GPS
Flag: reception status from external GPS
(non = OK, x= no GPS-data )
(course deviation: n = small, w = wide)
selected course:
After pressing HOLD GPS-course will be
copied into this field. It can be changed
up/down by +/-.
1.2.1 Definitions (Heading / Track)
SmartTrim gets the direction data from an external GPS , which are not influenced
by wind and magnetic deflections. So it concerns the true track (TT). That is why the
definitions “heading“ and “course” used for the SmartTrim are not fully correct.
However this does not change the basic functions of SmartTrim but it actually brings
only advantages.
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Filser Electronic GmbH
SmartTrim Xn
1.2.2 Control functions
By pressing the button MODE, the mode can be altered in sequence, at type X1
between HDG and WL (Wing Leveling) and at the type X2 from A+H to HDG to WL
and back to A+H.
At any selected mode, the SmartTrim can be activated by pressing the button HOLD.
The deactivation is done by pressing the button RELEASE for a short time.
While the SmartTrim is in the active status (HOLD), the abbreviation of the respective
mode is shown on the left in the upper line (at DIS the mode is shown on the right),
while the right side will display background information.
1.2.3 Second line
The second line is used for displaying the operation data. In the lowest level mode
(WL) it will display BANKn, where n is a number ranging from 0 to +/- 15
(0…9,A,B,C,D,E,F). This is useful, should the pilot want to fly a controlled turn at a
defined bank rate. The bank value can be changed by pressing the buttons + an -.
At the higher level modes (HDG, A+H) the second line shows the operation data for
the heading control:
Heading (default)
DIS HDG
- - - x000
Heading + Altitude (X2)
DIS H+A
- - - x000
Wing Leveling only
DIS WL
BANK 0
The operation line is structured as follows:
• The first 3 symbols contain the actual track being received from the GPSreceiver (which would be the actual heading in case of no wind)
• The 4th symbol is used as a status flag, also used for the GPS-reception
status.
• The last 3 symbols contain the required track.
When initially starting the device, the 4th symbol (status flag) will show an x,
indicating that there is no GPS-connection.
At the normal operation at this position other status symbols will appear as are:
Deviation from the required track: n small, w for large.
1.2.4 Heading pre selection :
After pressing HOLD the present GPS-heading will be copied into the lower right display
part.
With + and - the heading can be altered by steps at any time.
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Filser Electronic GmbH
SmartTrim Xn
1.2.5 Background information
While in the active status (HOLD, WL, H+A), the right side will display background
information.
In the mode HDG the internal calculated drift compensation value (due to the ceramic
gyros) to the left or right (<0…9>) is displayed. This only can be calculated while in
HDG-mode and it will be used for the WL mode to get symmetry for the bank.
Normally it should be less than 3.
In mode H+A, the offset of the pitch will be displayed in +/- degrees.
1.2.6 Examples:
HDG 1>
134n138
Heading-Mode:
Normal run on course with drift compensation to right
side and small deviation.
HDG 0
134 134
Heading-Mode:
Normal run on course, no drift .
HDG 0
134w270
Heading-Mode:
Course change (after button +++ or ----), presently the
course difference is large.
WL
0
BANK 4>
Wing Leveling-Mode:
In Wing Leveling mode turning right with app. 15°
bank .
The value for drift (0) results at internal calibration in
HDG-mode.
H+A -02
270n274
Cours + Altitude-Mode:
At top right, present pitch variation = -2°.
(downwards) on required course of 274°.
There are additional flashing characters between the
two indications showing the action for trim.
„+“ = Trim up,
„^“ = strong trim down,
„-„ = Trim down, „ _“ = strong trim down,
„ .“ = no action period.
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Filser Electronic GmbH
SmartTrim Xn
1.3 Summary of control functions:
ON: short push on RELEASE.
OFF: long push on RELEASE or turn off the power from external.
Mode indication on stand by is as follows:
MODE: DIS WL = (Wing Levelling = wing levelling)
MODE: DIS HDG = (Heading)
MODE: DIS H+A = (Heading+ Altitude)
Active modes, entry after press on "HOLD":
MODE: ATT = (Wing Levelling) Wing levelling
MODE: HDG = (Heading) hold present track on GPS or
go on route from DX-400
MODE: H+A = (Heading+ Alt.) lock on present altitude and
maintaining the actual GPS track
Default after power on is HDG for X1 and H+A for X2.
RELEASE: (DIS ...) turn off the control, set servo to the centre,
enable the trim for aileron.
The servo will be centred and the aileron is kept neutral by the springs.
After a complete turn off the servo is free running with the aileron.
Note: In case of dual-servo-system no aileron trim is possible !
Buttons + / - : in mode DIS = aileron-trim
in mode WL = set bank for aileron
in mode HDG = increment/decrement intended track
in mode A+H = increment/decrement intended track
(in case of no GPS data: increment/decrement of bank)
1.4 How to use
1.4.1 Disable (DIS)
The SmartTrim should be turned on for a sufficiently long time on ground at the
beginning of taxing and for the take off.
Remain in the mode DIS and fly the airplane against the force of the springs.
Of course, this presupposes that, as at the beginning described, the force of
the springs should be as low as possible.
The aileron trim should not be pressed immediately after switching on.
This time period gives the change to the SmartTrim to execute the necessary
calibration for the warm up process of the sensors.
Only in the DIS mode the aileron trim becomes possible on the buttons “+” and “-“.
(if factor D = 00, see at 2.4.2).
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Filser Electronic GmbH
SmartTrim Xn
1.4.2 Roll-Drift
As described under 2.4 with Factor B , the gyro for the roll-axis is subject to a temperaturedependent drift.
This drift will be compensated automatically through the GPS- control (mode HDG and A+H)
after a longer period (some minutes). The compensation value is shown in the mode WL.
In case there is a bad drift set-up, so after take off and first-time HOLD the course runs off to
one side until the end of compensation, then the chosen course will be established again.
The better the setting on Factor B is the less is this effect.
1.4.3 Horizontal reference
1.4.3.1 Pitch-Setup
A reliable control of altitude is only possible if the horizontal attitude of the airplane is
known. (about the pitch) To this a corresponding reference is necessary.
This process corresponds to the placing of the Vertical-Reference-Markers at a
mechanical horizon, with which the reference to the horizontal attitude of the airplane
is related.
Before the pitch set up can take place, the aircraft staying on the ground should be
aligned as is would be in a horizontal flight.
The initialisation for the pitch reference takes place by selecting the mode H+A and
temporary set to HOLD (enable), then pressing the keys “HOLD” and “+“
simultaneously.
This will be confirmed by a "i" in the display for the duration of approximately two
seconds.
It is necessary to turn on the unit for 5 minutes prior.
The reference value will be stored in the SmartTrim for the next use.
In case a set up of the pitch is necessary in flight, for example in the horizontal flight
or for tail wheel airplanes, this is possible by pressing the buttons "HOLD" & "+", in
the HOLD- condition and if the airplane is levelled off.
1.4.3.2 Pitch display
The difference between the pitch and the real horizon will be displayed on right hand
side in the upper line (+ /- nn while in HOLD condition), shown in degrees.
Like as at a usual mechanical horizontal gyroscope also in the SmartTrim the real
direction of plump will be found by a long time period (integration) of about 10° over
30 minutes, so any drift will be eliminated (only at pitch values less than +/- 6°).
1.4.4 HOLD for X2 (hold altitude)
If the HOLD- button will be pressed in the normal flight condition at mode H+A, so
the actual course and the present height are captured as set values for the control.
If this takes place in the ascent, for example, so a Level-Off is introduced which leads
to some oscillation around the debit height.
It is better to make first a manually level off before pressing the button HOLD.
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Filser Electronic GmbH
SmartTrim Xn
1.4.5 Quality of altitude control
The precision of the altitude control depends strongly on the influence of the vertical
air movement (thermion, gusts). Since the technical expenditure must be restricted
for cost reasons, the pilot will be always better than the automation.
With stronger thermion, it therefore is advisable not to go in for automatic hold of
altitude.
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Filser Electronic GmbH
SmartTrim Xn
1.5 Coupling.
1.5.1 General information
In case the SmartTrim is connected to a navigation system where an additional
NMEA- format “RMB” is supported, instead to a normal GPS receiver the SmartTrim
is able to follow a prepared course line.
Before activation a prerequisite is that the aircraft is set up on this course line. The
required course at right lower line on display should be identical with the bearing to
the next destination and the position of the aircraft should not more than +/- 9nm off
the line.
SmartTrim is able to capture a line within +/- 50° off course.
A deviation between the set up track and the true track (max. +/-50°) results into an
parallel offset.
1.5.2 Handling
The aufschaltung can be activated by pressing the buttons “+” and “-“
simultaneously. The confirmation appears in mode A+H by replacing the “A” firstly by
an “x” which will be changed to a “B” after having received the first data from the
RMB-format out of the navigation system.
The same symbols appear in the HDG mode but immediately after the “G”.
Example activating the aufschaltung
H+A -02
123 n 124
HDG >1
123 n 124
>
>
x+A -02
123 n 124
>
B+A -02
123 n 124
HDGx >1
123 n 124
>
HDGB >1
123 n 124
To deactivate the aufschaltung just change the mode, e.i. to turn off quickly staying in
the same mode, press mode button three times.
While the aufschaltung is active SmartTrim can be changed between DIS (disable)
and HOLD (enable).
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Filser Electronic GmbH
SmartTrim Xn
2 Installation
2.1 Mechanical installation
2.1.1 Type of servo drive:
Two different servo-systems for the aileron are possible..
The standard version consists of only one servo. Here also in the mode „disable“ the
aileron is always held in neutral position with minimum force by two spiral springs,
which the pilot can surmount easily (not notable).
If this constant resetting force is not desired and a complete release of the aileron
with switched off SmartTrim demanded, then alternatively a double servo mechanism
can be used. Here two identical servos are operating parallel next to each other. All
functions remain the same, as long as SmartTrim is active. With Smart Trim
switched off the Servos runs apart into its opposite final positions, so that no more
forces can affect the aileron..
2.1.2 Easy installation of the servo to the aileron:
At a suitable place on the aileron push rod circuit, the servo system can be
connected using a cable and springs, as shown below.
The strength of the spring has to be selected such that the pilot can easily overpower the demands of the servo system, in the event of a mal function.
Aileron thrust bar (moving against the stick direction)
1mm-V2A-Seil
44
The wheel has a rotary area from + / - 90°.
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Filser Electronic GmbH
SmartTrim Xn
This permits movement of 69mm max. (using 44mm diameters).
In case this is not enough, a wheel with a bigger diameter should be selected.
In any way the full range of the aileron should be fitted to a half revolution of the
wheel.
The dimension (stiffness) of the springs should be in such a way, that the servomotor
in the off condition runs just along well and simultaneously an overload (with
servomotor is in on condition) should not over expand the springs at full manual
movement of the aileron.
The two springs should be so pre-stretched that they are lengthened
approximately in neutral position about ¼.
A tried dimension to get the correct stiffness is a wire diameter raging from 1,5 to 1,8
mm, a spiral inner diameters from
12-15 mm and 15 to 20 turns. The mobility of the entire aileron must be as smooth
as possible and without friction.
Attention:
The software up to version „i“ does not provide the reversal of the movement
polarity..
The software has no set-up for reversal of the movement polarity in the X1-Version.
If an opposite control is necessary for mechanical reasons, this can only be realized
by an inverted rope action.
2.1.1.1 Check of the spring tension
When switching on the SmartTrim , the aileron should place itself spontaneously into
the middle, with must take place also at small offsets from the neutral position. As
well when trimming, (buttons + / -) each step must be recognizable at the stick.
During a separate test flight determine the amount of force and displacement
necessary for the smallest detectable effect.
On ground in standby mode you should find the same or max. twice the force at the
same value of displacement.
2.1.3 Installation of the double servo mechanism to the aileron:
In case there is absolutely no tension allowed to the aileron if SmartTrim is in the off
condition, optional a dual servo system can be applied.
In principle here the same requirements apply to the attitudes of the springs and the
operational behaviour. The difference exists only in the use of two identical working
servos next to each other, each servo acting for one direction. Electrically the two
drives are switched parallel.
The spring pre-stretch should be a minimum and the stiffness should be app. twice
against the single servo principal.
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Filser Electronic GmbH
SmartTrim Xn
In the dead condition both Servos are pulled by the springs from their central
position into the opposite mechanical final positions and remain there. The safety
springs have the primary task to hold the rope under slight tension so that the loose
rope does not fall from the guidance. The calculation of these weak and soft springs
(also a thin rubber cord can be used) does not have to influence the operation.
Querruder-Schubstange (Bewegung entgegen dem Knüppel)
1mm-V2A-Seil
1mm-V2A-Seil
Seilsicherungs-Feder
Seilsicherungs-Feder
44
44
Doppel-Servo
Note: For dual-servo-system no aileron trim is possible !
2.1.4 Control of the elevator (X2 only)
For version X2 an additional control for the elevator takes place using the
specific aircraft build-in electric trim.
X2 controls the altitude levelling by using the existing elevation trim of the respective
aircraft. X2 and the pilot share the access to the existing electrical elevation trim.
It is a prerequisite that the existing electrical elevation trim is operated by buttons
which are connected to a logical circuit (relays). This ensures that competing access
of both X2 and the pilot will be ignored. The result should be no action, just as if the
pilot would press both buttons simultaneously.
X2 has two output lines, one for stepping up and one for stepping down. These lines
can be connected to the up- / down-buttons in any order. The software setup of X2
supports swapping of the direction-assignment of these lines.
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Filser Electronic GmbH
SmartTrim Xn
2.2 Wiring
2.2.1 General
Because each different type of aircraft provides different dimensions and positions for
the servos no standard wiring system is possible. The wiring diagram at the end of
this document describes the hole interconnection.
Filser provides extra support manufacturing a cable harness based on customer
requirements and dimensions.
2.2.2 Wiring for the vertical axis (X2 only):
To control the aircraft trim system for
holding the altitude, the SmartTrim will
switch both the signals (pin 2,3) to
ground, individually for a short period.
These signals needs to be connected in
parallel to the trim buttons of the aircraft
trim system. For the time being at the
installation, the direction-assignment
does not matter.
The max. load for the source circuit of
the SmartTrim is 5 A for a max. voltage
of 30V.
SmartTrim
Manual trimming buttons
Diodes 100V/1A,
or resistors 220Ohm / 0,5W
Two Relais
The external relays have to be clamped
by an anti parallel diodes or resistors to
prevent over voltage due to induction.
Also the servo motor should be have a
good EMV protection.
+12V (main)
Capacitor (1uF/100V)
M
Servo motor
2.2.2.1Test
To ensure a correct wiring a test is necessary. While the power of the trim system is
on, the pins 2&3 of the SmartTrim plug at the open cable tree should be shortened to
ground individually and simultaneously. When connecting only one pin, the trim also
must move in the related direction. If both are connected, nothing should happen.
2.2.3 GPS source
For heading control, GPS-data will be used at a format NMEA-RMC and
4800baud. The data refresh must be once a second. Some GPS receivers
with an update sequence of only every other second are not sufficient
(some of GARMIN’s). Sources like these are leading to a flashing track display
and a bad heading control. In case of use with coupling additional the sub format
RMB is required.
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Filser Electronic GmbH
SmartTrim Xn
To avoid interface problems Filser provides a special aviation GPS-Mouse for save
operation.
2.3 Attitude of the SmartTrim instrument
Especially to the altitude control (X2) it is important that SmartTrim is aligned as
horizontally and parallel to the airplane longitudinal axis as possible, just as this is
required also for a gyroscope horizon.
Also for X1, a similar, even if not so exactly horizontal mounting situation makes
sense.
In case the Filser GPS-mouse is in use the position of it should be so that it has a
free reception from the vertical (e.g on top of the instrument panel).
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Filser Electronic GmbH
SmartTrim Xn
2.4 First time set up
2.4.1 Set up of the roll axis
1.) After switching on, the servomotor is in a neutral position. At this point the
mechanical neutral position of the steering has to be adjusted. After that, the
trim function has to be checkable with the buttons + and - . Likewise here,
the swing range, as well as the possible overstretching of the springs (from the
mid position of the stick) has to be controlled.
2.) Starting point for the adaptation to the airplane features is always the WLMode (Wing Leveling control). After switching on, however, the device default
turns to HDG mode and must be switched to the WL mode first.
3.) In mode DIS (and Regelfaktor D =00) the buttons + and – should be pressed
while the joystick has to be watched. The button + should move the stick to the
right while the – should move it to the left. In case the direction is wrong the
related bit of the control factor E should be changed (only possible after
version “i”).
4.) Press HOLD in the WL-Mode, the stick probably starts to drift slowly into a
direction. This would correspond to a slight course alteration (bank) in flight.
With small alterations of the bank (+ / -) this stick-drift must be able to be
compensated. A bank more than 2 should be accepted at first. Only after the
flight test and a continuous drift in the same direction, the factory default value
should be changed to the regulation factor D. By pressing REL the stick
returns to the neutral position, that is the last trim position.
5.) Further tests can be executed only in flight, in fact only in the WL-Mode and in
as quiet as possible air! The points 1-3 need to be repeated analogously.
The defaults correspond to a very dynamic airplane, so that no instability
(oscillations) should to be expected, as soon as (coming from WL) HOLD is
pressed.
If against expectations the airplane should react unstable, press REL
immediately.
After step-wise reduction of the regulation factor A, further attempts must be
done.
If this brings no improvement, all requirements need to be checked again and
if no recognizable mistakes are found, the factory has to be contacted.
If the airplane responds equivalently right and faultless and regulates proper to
disturbances and gusts, the testing of the HDG-mode can take place.
If the airplane responds too indolent and partially not, further attempts through
increasing of regulation factor A step-by-step must be made.
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Filser Electronic GmbH
SmartTrim Xn
If these attempts are not satisfactorily, please contact the factory.
6.) The test of the course regulation requires the correct data supply from an
external GPS. If an X in the flag-field appears, the problem of the data source
needs to be solved first. Our company will be helpful here. If other letters
appear in the flag field than described, a disturbance of the GPS-data should
be expected (see GPS source). The further testing of the course management
should be possible without problems under the correct prerequisites. With the
regulation factor A & C, fine oscillating movements can be optimised at the
course posture.
7.) In case of using the douple-Servo finally the bit 1 has to be set in Factor D
(hex 02), so that in mode DIS the two servos will be released. That means the
aileron trim is turned off while in DIS-mode.
2.4.1.1 Rolldrift-Setup
This serves normally only for the first time set up for the off set at the roll sensor with
storage under control factor B. The conditions are alike as with the PITCH Setup,
however the mode WL (wing leveling) has to be set before and disabled. In flight
this is to be avoided, as the air rarely is calm enough to receive no faulty
measurement.
Control:
Switch on SmartTrim again and wait for minimum one minute.
Pres HOLD key again (enable).
The aileron is to need longer than one minute to reach the limit with the drift.
2.4.2 Set up of the pitch axis (X2 only)
2.4.2.1 Adapting the pitch trim
1.) After the first turn on a check has to be made if the direction of pitch trim and
size of trim steps are correct. Therefore the control factor D should be set to
01.
2.) The control factor H should be set to a higher value for test only (e.g. 09...0F),
because if a slow (lazy) trim servo is in use no reaction could be the result.
3.) In mode DIS (and Regelfaktor D =01) the buttons + and – should be pressed
while the trim has to be watched. The trim should make steps once per
second. The button + should pull the trim and the – should push it. In case the
direction is wrong the related bit of the control factor E should be changed .
4.) The relays circuit for the pilots trim buttons (where the SmartTrim acts parallel
too) needs to be checked for correct operation. In case the pilot is pressing
any button a simultaneous action of SmartTrim should make no effect. If so
the trim should make nothing. This is an identical effect as if the pilot is
pressing both the trim buttons simultaneously.
5.) Now the control factor H should be reduced that much, that the size of steps
becoming a minimum until the trim seems to stop reaction. The goal is to
make the steps as small as possible but sufficient to move the trim.
6.) Change back the factor D to 00.
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Filser Electronic GmbH
SmartTrim Xn
Note: The point 3 is only possible starting from software-Version "g". The trim
polarity can be determined alternatively only by change of situation of the
SmartTrim's and observation of the trim reaction.
2.4.2.2 Pitch-Setup
The airplane should stay on ground in a position, which corresponds as much as
possible to the horizontal flight attitude. The SmartTrim has to be active for at least 5
minutes .
Select H+A mode (already exists by switching on), Press Button „HOLD“ (enable)
and then the combination of keys "HOLD" and "+". The confirmation takes place via
an "i" in the display for the duration of approx. two seconds. Press again RELEASE.
Control:
Switch on SmartTrim again and wait for 1 min.
Press again HOLD (enable).
Observe PITCH-display, which firstly may not be larger than +/- 03 , then should drift
gradually verso 00.
2.4.2.3 Calibration of control factors F(Pitch- tolerance- window) and
G(Pitch-trim period)
Depending on the typical dynamic of the aircraft in use the both factors can be
optimised, started on the default values. For high dynamic aircrafts like the MCR01
(Banbie) the default values can be used.
The actions on the vertical trim are oriented on a fix time raster which can be set up
with control factor G. The raising value of the set up number doubles the raster time,
while 00= 1,7 sec., 01=3,5sec., 02=7sec.....
Aircrafts having a high stability on elevation axis requires higher raster time values
like 02 or 03.
The control factor F defines the window of tolerance for the altitude. A small value
like FC results into unnecessarily high correction activity.
2.5 Behaviour of X2 without GPS-Data
If no GPS- data are available for the course control, the SmartTrim behaves in a way
that the Heading-Mode (HDG) is reduced to the functions of the Wing Levelling-Mode
(WL).
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2.6 Overview parameter setting
For first time initialisation and adaptation to different aircrafts, special commands are
available. Therefore one needs to press the designed buttons together and in the
designed sequence.
2.6.1 Commands
(press buttons together in this sequence)
Select SETUP:
select parameters:
change parameter
save/exit SETUP:
"Mode" & "+"
"+" / "-"
"Hold" & "+" / "-"
"RELEASE"
Set default:
in SETUP mode: "Mode" & "Hold"
Read back parameters: "Mode" & "+" and ++++ ---
2.6.2 Aircraft characteristic parameters
Note: All the following numbers are represented in Hexadecimal. The range of one
figure is 0....F (0...15). The range of the two column number is –127 (80h) to +127
(7F), -1 means FF, -2 means FE, +1 means 01, +2 means 02 and so on.
Default for MCR01 = [ ]; range of variation = ( )
2.6.2.1 Roll axis until version X1B
A
B
C
D
:
:
:
:
Control factor 1...10 [6]
offset for roll gyro [xx] (for control only)
Small window width for hold course (00...02) [01] (01=2°)
Initial roll-gyro offset (E0..00..20) [FE] (depends on temperature)
2.6.2.2 Roll axis for version X1/2C and later
Factor A: Control factor 1...10 [4]
Represents the gain for the closed loop control (SmartTrim and aircraft). In
case this value becomes too large, the course correction results into a too
larger change in rolling, which leads to an oscillation. If this value becomes too
small, a shiftless will be the result and a wing will hang.
Factor B: Initial roll-gyro offset (E0..00..20) [FE] (depends on temperature)
FE is just an example; this value is preset at a factory individually.
FE is a hexadecimal value representing -2. Neutral is 00.
For calibration, change it in small steps only and after a warm-up time
of more than 5 minutes. Therefore, on ground, the drift of the stick
should be as small as possible after setting WL-HOLD.
Note: This offset is temperature sensitive. It needs to check after big
temperature changes.)
From version "K" onwards, this setting has been automated.
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The Drift-Setup will be activated by pressing the button combination "HOLD"
and "+" in the WL-Mode . This is shown by a "i" in the display for the duration
of approximately two seconds. This process can take place only at the ground
(quiet situation) and after approximately 5 minutes of run time.
In case a troublesome offset (initial course leeway) should appear during the
flight, this Drift-Setup must not be executed while flying, but the Factor B has
to be changed accordingly.
Factor C : Small window width for hold course (00...02) [02] (01=2°)
Is used for fine adjustment of the heading, if the aircraft in on the track.
This value needs to be tested in non-turbulent air.
Factor D: For single- Servo always 00.
In case no force is allowed in DIS –mode (only possible with a double servo)
then the aileron trim is not available.
If required the servo becomes inactive on DIS if D= 02.
2.6.2.3 Elevation axis (X2 only)
(Variation range) [Value for MCR01]
Factor D: see on previous description for D, additional for temporary test of the
elevation trim 01 (or 03 at double servo if required).
Factor E: Polarity: Bit 0 = Pitch-Trim, Bit 1 = Roll-Trim. [01]
The right two bits are used as a switch for swapping of the direction-assignment
between SmartTrim meaning and alevator/aileron (after version j, before elevator
only) :
elevator
pos.
neg.
pos.
neg.
aileron
pos.
pos.
neg.
neg.
Factor E
01
00
02
03
Factor F: Pitch tolerance window [FC] (FE,FC,F8,F0) (FE is small, F0 is large)
Is used to stabilize the altitude control at turbulent air conditions. The meaning is
a tolerance window (hex-mask FE …) for small variations the pitch. If this window
is too small many corrections at a time will be the result. This will stress the trim
mechanism too much. In case this window is too large (F0,F8) the precision of the
required altitude becomes worth.
At version “L” the mask technique has changed for a numerical value [04] (03
...08) {04=+-3°}.
Factor G: Pitch-Trim period [01] (00,01,02,03..) [01] (0=1,7sec.; 1=3,5; 2=7;...)
Is similar to F, but it is dependant from the physical shiftless of the elevation axis
of the corresponding aircraft. For aircrafts having a significantly long fuselage as
the MCR01, the factor G should become larger (07..0F).
Factor H: Pitch correction duration (01, 02, 03..) [02] (01 = 0.05 sec)
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Denotes the time period for acting the trim buttons for a minimum correction.
Special attention should be paid to H, because this time lapse is extremely
dependant to the mechanical performance of the trim installation of the
corresponding aircraft. The correct value is that, where the reaction is so small
that it just is recognisable. In case H is too large the aircraft starts to jump up and
down. If it is too small no reaction will occur.
Factor I: Time constant for elevation correction on turns [18].
Delay, should never be changed. For a controlled turn (+/- >90°) a pitch
correction with a delay is required, which should prevent diving down the aircraft
while on a turn.
Factor J: Coarse correction at large pitch deviations [10] (app. 10x Factor H)
Defines an emergency correcting value for big pitch deviations (climbs or decent
angles) at more then 7° pitch. This action is indicated on display with the signs “^”
or “_”.
2.7 Special hints
Sometimes it may be necessary that the original servo can not be used and other
servos from the market will be implemented.
In that case it is very important to look at the quality of that products.
Several times we got the experience, that this products did include low cost
potentiometers which are essential for the mechanical position finding.
After a short runtime this units going to start uncontrolled movements which can not
be handled by the SmartTrim.
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3 Technical data:
3.1.1 Overview
•
•
•
•
Intelligent trim for one or two axis for
doing the job of a full auto pilot.
Small size (diameter for panel mount = 57 mm).
Two line LCD-Display for status, heading, reference altitude.
First axis for "Wing levelling" and true track following a pre selected GPS-track.
Second axis for altitude levelling.
Display shows:
Mode:: Bank (at Wing Leveling), Heading, Heading & Pitch
For Heading: required track, and actual track.
Type definition:
X1: uses 1 ceramic-rate-gyro and data from an external GPS
receiver, driving a servo on aileron for wing levelling
and course (true track).
X2: extension of X1, using a second ceramic-rate-gyro
and additional three sensors, with an additional output to
vary an existing elevator trim.
3.1.2 Data
Power consumption:
Voltage:
Dimensions:
Weight:
Source for trim control:
Accuracy: Track control
Altitude control
app. 50 mA + power for servo
9.5...35 V
diameter 57 x 80 mm + connector
app. 200 g
1 A at max. 30V
+/- 1° long time, +/- 8° temporary.
+/- 100ft to +/- 200ft dependant on turbulence.
3.1.3 Connector pinning:
Type Sub-D 9pin
(use female for external)
[colours are corresponding to servo cable]
1 = Power DC 10...18 V [pink]
2 = Altitude trim + [violet]
3 = Altitude trim - [yellow]
4 = GPS input (NMEA-RMC, 4800 baud) [blue]
5 = GND [black]
6 = external RELEASE, ON/OFF [green]
(for control stick, set to GND)
7 = 6V power out for servo [red]
8 = control of servo (PWM) [orange]
9 = GND for servo
[brown]
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