Wuxi LingDe Microelectronics LD902NU User manual

WUXI LINGDE MICROELECTRONICS CO., LTD.
LD902NU Display
Instruction Manual
V1.0
2017/10/11
The instrument-LD902NU is simple and beautiful with the unique design of
scientific ergonomic curve.The LED is not only clearly visible in the sunlight but also
displayed with soft light under the night mode that makes riding safety.

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About our Manual
Please read the manual of LD902NU carefully before taking
a ride for a better performance.
Size

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Model and parameter
LD902GU
Five assisted power display
Level 0 to 5 assisted power display
Standard USB to charge your phone
RS232
Support 24V,36V,48V
Installment guide
1.Fix the instrument on the handlebar and adjust a
appropriate angel.
2.Install the set screw from the bottom of instrument fixed
on the handlebar. It is advised to install the screw
manually.
3.Please insert the connectors of instrument and the
connector of controller on the occasion of power off.

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Definition of button
There are 4 buttons on the instrument,including the
power/mode（M）,up( + )，down( - )and headlight switch（B）.
Routine operation
turn on/ off
ON: press the button of M for a long while on the occasion
of power off, and enter the password if any , then the
instrument starts working , offering the power to controller
and working well with controller after 3 seconds .
OFF: press the button of M for a long while on the occasion
of on , you can turn off without wasting the power.At this
time ,the current is less than 1uA.
Assisted Power Select
Press the button of + or - for a short while , you can change
the output power of motor. The default power ranges from
level 0 to level 5, 1 the lowest, 5 the highest. When the
instrument is on,the default level is 1 just like the red box in
picture below.

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PowerAssisted Walk
After holding the button of DOWN for 2 seconds, electric
bicycle will come into the mode of power assisted walk,
keeping an even speed at 6 kilometers per hour. The gear
position displays the speed per hour. Release the button to
stop the mode immediately.
Notes:
The function works out at the situation of pushing electric
bicycles. Do not use it when riding.
Turn on/off headlight
Press the key（B）to turn on the headlight，
press the key again to turn off it.Key on
the side of the device.
Display of handover
The instrument will display the current speed and ODO on
the occasion of normal work without breakdown. When
pressing M, you can switch to AVG and TRIP, with the
corresponding indicator light on.

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Capacity display
When voltage is high, 5 battery segments will be alight;
when only 1battery segment is alight , it means low power
and needs to be charged.
Error code display
When something is wrong with the electric control system,
the ERR light will be alight and speed position will show the
error code .
Only when the fault is excluded can it exit the interface. If
the fault happens, the bicycle cannot be ridden.
Parameter setting
In setting menu: You can do settings when pressing + and
-,and entering the password 1234 on the occasion of
power on and normal work of the parking instrument,
just like SE and number 1 in the picture below. (Please
note that some types do not have password) You can set
the number password by press + and - for a short while.
You can set the next number password by pressing M
for a short while. Do the same work till entering the
correct password and coming into the interface of
setting items.

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EXIT Menu:You can exit the setting menu by pressing M
for a long while in any setting menu.Besides, you can
exit the setting menu automatically by pressing M for a
short while and switching all the setting items.
SET1(unit setting): When entering the setting menu, the
default setting is SET1. You can switch the mile and
kilometer by pressing +/-, with the switching of speed
and trip at the same time and corresponding indicator
light on. You can quit the interface by pressing M to set
the next item for a short while or pressing M for a long
while.
SET2(speed limited): When in SET2, the factory default
limited speed of the instrument is 25km/h. The
effective limited speed ranges from 10 km/h to 41
km/h by pressing +/-. It doesn’t work if over the

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range. You can quit the interface by pressing M for a
short while to set the next item or pressing M for a
long while.
SET3(Wheel diameter setting)when in the mode of SET3,
the default wheel diameter matches the whole
bike, so it is not advised to change it. The wheel
diameter can be changed by pressing the key of
+/-, including 16 20 22 24 26 700C 28. You can
enter the next mode by pressing the key of M.
Set4 (magnetic steel of speed measuring):when in the mode
of set4,the default magnetic steel of speed
measuring matches the whole bike. The default
value is 1 if no exclusions. The number is not
advised to changed . You can change it by
pressing the of +/-. 1 and 6 can be chosen. You
will go into the next setting by pressing the key of
M for a short time.

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Set5(the total gear setting): when in the mode of set5, the
default total assisted gear is 5. You can change it
by pressing the key of +/-, with the maximum 9
and the minimum 1.ou will go into the next
setting by pressing the key of M for a short time.

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Quality Warranty
一、warranty coverage：
1、When the malfunction is caused by the quality of the
product itself under regular use condition，our company will
be responsible for it under guarantee.
2、24 months from the delivery time of the display out of the
factory.
二、The following conditions are not covered by the
warranty.
1、The shell is open.
2、The connectors are broken.
3、The shell is scratched or damaged after out of factory.
4、The lead wires from the display are scratched or broken.
5、Damages are caused by irresistible (e.g. fire, earthquake,
etc) or natural disasters (such as lightning, etc.);
6、The product exceeds the warranty period.

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Wiring Diagram
The display is matched with 5-waterproof wire and the wire
definitions are as below.
number
colour
function
1
Red (VCC)
Power B+
2
Black(GND)
Power B-
3
Yellow(TX)
Gorge line: sending message
4
Green (RX)
Gorge line: receiving message
5
Blue (K)
Electric door look offer weak power
to other equipment
Note：Users cannot see the color of the internal wiring
because of the water proof connector.