Key-Disp KD31M User manual

Content
Product name and model..........................................................................................................................................1
Specifications..............................................................................................................................................................1
Appearance and Size................................................................................................................................................ 1
Function Summary.....................................................................................................................................................2
Button Definition......................................................................................................................................................... 2
Monitor Area................................................................................................................................................................2
General Operation..................................................................................................................................................... 2
◆Switching the eBike System On/Off............................................................................................................... 2
◆Displaying Interface...........................................................................................................................................2
◆Switching Push-assistance mode On/Off......................................................................................................2
◆Switching the Lighting On/Off..........................................................................................................................3
◆PAS Level Selection..........................................................................................................................................3
◆Battery Indication............................................................................................................................................... 3
◆Error Code Indication........................................................................................................................................ 3
Trip Distance Clearance........................................................................................................................................... 3
General Parameter Settings.....................................................................................................................................3
◆Wheel Diameter Settings..................................................................................................................................3
◆Speed-limit Settings.......................................................................................................................................... 4
◆Assistance Level Settings................................................................................................................................ 4
Quality assurance and warranty scope..................................................................................................................4
Connection layout...................................................................................................................................................... 5
Operation Cautions.................................................................................................................................................... 5

1
Product name and model
Intelligent digital display of eBike, model: KD31M.
Specifications
●24V/36V /48V Power Supply
●Rated working current: 10mA
●The maximum working current: 30mA
●Off leakage current: <1uA
●The supply controller working current: 50mA
●Operating temperature: -20 ~ 60 ℃
●Storage temperature: -30 ~ 70 ℃
Appearance and Size
Display appearance and dimension figure (unit: mm)

2
Function Summary
KD31M can provide a lot of functions to fit the users’ needs. The indicating contents are as following:
●Smart Battery Indication
●Assistance-level Indication
●Running Speed Indication
●Trip distance and total distance
●The push-assistance function
●The Lighting On/Off
●Error Code indication
●Various Parameters Settings (e.g. wheel size, PAS level, etc.)
●Recover Default Setting
Button Definition
There are three buttons ( , , ) on the KD31M display that represent the following functions
respectively MODE, UP, DOWN.
Monitor Area
Monitor Area
General Operation
◆Switching the eBike System On/Off
To switch on the eBike system, hold the MODE button for 2 s.
In the same way to hold MODE button for 2 s again, the eBike system will be switched off.
When switching off the eBike system, the leakage current is less than 1 uA.
■When parking the eBike for more than 10 minutes, the eBike system switches off automatically.
◆Displaying Interface
The display consists four displaying state interfaces, respectively is the Running Speed, Battery
percentage, Trip distance and Total distance, the default value is Running Speed.
When the eBike is parked, briefly press the MODE button, the display can in turn circular display Battery
percentage, Trip distance and Total distance, every state displays 2 s and then automatically returns to the
Running Speed interface.
When the eBike is riding, press the MODE button, the display can in turn circular display Battery
percentage and Trip distance, every state displays 2 s and then automatically returns to the Running Speed
interface.
◆Switching Push-assistance mode On/Off
To access the push-assistance mode, hold the DOWN button for 2 s, the eBike will go on at a uniform
speed of 6 Km/h, “P” is showed on the screen at the same time. The push-assistance function switches off
as soon as you release the DOWN button.
Push-assistance mode

3
■Push-assistance function may only be used when pushing the eBike. Danger of injury when the
wheels of the eBike do not have ground contact while using the push-assistance function.
◆Switching the Lighting On/Off
To switch on headlight of the eBike, hold the UP button for 2 s.
In the same way to hold the UP button for 2 s again, the headlight will be switched off.
◆PAS Level Selection
PAS Level indicates the output power of the motor. The default value is level “1”.
The default power ranges from level “0” to level “5”. The output power is zero on Level “0”. Level “1” is the
minimum power. Level “5” is the maximum power. Gearing to level “5” and then pressing the UP button, the
interface shows “5” still and “5” flashing prompts top. Gearing to level “0” and then pressing the DOWN button, the
interface shows “0” still and “0” flashing prompts low.
To change assistance level, press the UP/DOWN button to increase or decrease until the desired
assistance level is displayed.
PAS Level selection interface
◆Battery Indication
Battery indication is displayed by percentage.
Battery percentage display
◆Error Code Indication
If there are errors about the electronic control system, the error code will appear automatically. Here is the
message of the error code in Attached list 1.
Error Code Indication
Trip Distance Clearance
To clear trip distance, hold both the MODE button and the DOWN button for 2 s.
When the eBike is parked, the display shows 0.0KM for 2 s and then returns to the interface of Running
Speed automatically.
General Parameter Settings
To access the General Parameter Settings state, hold both the UP and DOWN button for 2 s.
To access the corresponding settings page, press the UP/DOWN button to increase or decrease until the
desired item is displayed,and then press the MODE button to confirm.
◆Wheel Diameter Settings

4
Ld represents Wheel Diameter. Electable values are 16, 18, 20, 22, 24, 26, 700C and 28.
The default value is 26inch.
To change basic settings, press the UP/DOWN button to increase or decrease until desired value
of wheel diameter is displayed.
To store a changed setting and access previous interface, press the MODE button.
To store a changed setting and exit General Parameter Settings interface, hold the MODE button for
2 s.
Wheel Diameter Setting Page
◆Speed-limit Settings
LS represents the limit speed settings. When the running speed is faster than limit speed, the eBike
system will switch off automatically. Limit speed ranges from 12Km/h to 40Km/h. The default value is 25Km/h.
To store a changed setting and access previous interface, press the MODE button.
To store a changed setting and exit General Parameter Settings interface, hold the MODE button for
2 s.
Limit Speed Setting Page
◆Assistance Level Settings
In assistance level settings, there are 8 modes to select:0-3, 1-3, 0-5, 1-5, 0-7, 1-7, 0-9, 1-9. The default
value is 0-5.
To change the mode of assistance level, press the UP/DOWN eBike button to increase or decrease until
the desired setting is displayed.
To store the changed setting, press the MODE button.
PAS Mode Select Page
Quality assurance and warranty scope
ⅠWarranty
1) The warranty will be valid only for products used in normal usage and conditions.
2) The warranty is valid for 24 months after the shipment or delivery to the customer.
ⅡOthers
The following items do not belong to our warranty scope:
1) The display is demolished.
2) The damage is caused by wrong installation or operation.
3) Shell of the display is broken when the display is out of the factory.
4) Wire of the display is broken.
5) Beyond Warranty period.

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6) The fault or damage of the display is caused by the force majeure (e.g. fire, earthquake, etc,).
Connection layout
Connector line sequence
Display-side Connector Display-side adapter Switch wiring
Line sequence table
Line sequence
Color
Function
1
Red（VCC）
+
2
Blue(K)
Lock
3
Black(GND)
-
4
Green(RX)
RX
5
Yellow(TX)
TX
■Some wire use the water-proof connector, users are not able to see the inside color.
Operation Cautions
Be care of the safety use. Don’t attempt to release the connector when battery is on power.
◆Try to avoid hitting.
◆Do not modify system parameters to avoid parameters disorder
◆Make the display repaired when error code appears.
Attached list 1：Error code definition
Error Code
Definition
E21
Current Abnormality
E22
Throttle Abnormality
E23
Motor Abnormality
E24
Motor Hall Signal Abnormality
E25
Brake Abnormality
E30
Communication Abnormality