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version instructions note
V101 Original version, standard frame format
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V102 Increases the cumulative discharge timing
BMS-CAN communication protocol
1 overview
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This protocol specifies the communication protocol between the BMS and other nodes in the automotive CAN network.
2 Definition of Terms
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BMS: Battery Management System.
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Can: Controller Area Network;
3 Physical interface
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This agreement adopts CAN2.0A standard, and the frame format adopts standard frame.Communication baud rate is 250kbps.
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The communication between the BMS and the instrument is point-to-point one-way communication, that is, the
BMS sends data to the instrument, and the instrument only receives and interprets the data for display.
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4 Data convention
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In the data transmission of this protocol, low-byte first-send mode (small-end) is adopted for multi-byte data, except for
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special instructions. For the battery's total current value, a positive value indicates discharge and a negative value indicates charge.
The data format of this Agreement is defined as follows:
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CANJD Data fields
FUNC SA DATA
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3 8 0 ~ 64
Func is the function code that represents the frame data type.
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SA is the source address, here represents the address of the BMS, fixed as 0xF4.
Data refers to DATA domain information, and the frame length of this protocol is fixed at 8 bytes.
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5 Parameter group number
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The parameter group number is assigned as follows:
The The name of the describe FUNC ID The sender Message cycle
serial Battery status
1 BATT ST 0x02 0x02F4 BMS 20ms
information
2 CELL VOLT Batteries voltage 0x04 0x04F4 BMS 100ms
3 CELL TEMP The cell temperature 0x05 0x05F4 BMS 100ms
4 ALMJNFO The alarm information 0x07 0x07F4 BMS 100ms
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Messages of battery status, cell voltage and cell temperature are sent periodically after power on, and alarm message in an
event triggered manner
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6 Message Definition
6.1
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Battery Status (BATT ST) ID: 0x02F4
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This message defines power battery status information. The specific format is as follows:
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The parameter Start bit A length of The scope of The The offset unit note
serial
1 BattVolt 0 16 0 ~ 1000 resolution
0.1 of 0 V Total voltage of battery
2 BattCurr 16 16 - 400 ~ 1000 0.1 - 400. A pack current
3
4
SOC
DischgTime
32
48
8
16
0-100.
0 ~ 65535
1
1 MS
0
0
%
h
Total battery
The residual capacity
Discharge time
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For example :02F4 13 01 D7 11 33 XX 64 00
Represents: voltage 27.5V, current 56.7A (precision: 0.1A), SOC51%, discharge time 100h.
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6.2 Cell voltage (CELL_VOLT)ID: 0x04F4
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This message defines the cell voltage information. The specific format is as follows:
The parameter Start bit A length of The scope of The The offset unit note
serial
1 MaxCellVolt 0 16 0 ~ 5000 resolution
1 0 mV Maximum cell voltage
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2 MaxCvNO 16 8 1-250. 1 1 Highest cell n o .
position
3 MinCellVolt 24 16 0 ~ 5000 1 0 mV Minimum cell voltage
4 MinCvNO 40 8 1-250. 1 1 Lowest cell n o .
For example: 04F4 8C 0A 05 92 09 08 XX XX
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Represents: the highest cell voltage is 2700mV, corresponding cell number is 5;The lowest cell voltage is 2450mV, and the
corresponding cell number is 8.
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6.3 Cell temperature (CELL_TEMP)ID: 0x05F4
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This message defines the cell temperature information. The specific format is as follows:
The parameter Start bit A length of The scope of The The offset unit note
serial resolution Maximum cell temp
1 MaxCellTemp 0 8 - 50 ~ 200 1 - 50 ° c.
2 MaxCtNO 8 8 1 1 Maximumt temp no.
1-250. p o s i t io n
3 MinCellTemp 16 8 1 - 50 ° c. Minimum cell temp
- 50 ~ 200 temper
4 MinCtNO 24 8 1 1 Lowes temp no.
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1-250 position
5 AvrgCellTemp 32 8 - 50 ~ 200 1 - 50 ° c. Average cell
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For example: 05F4 48 06 2F 01 3F XX XX XX
temperature
Represents: the highest cell temperature is 22°C, corresponding cell number is 6;The minimum cell temperature is -3°C,
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corresponding cell number is 1.Average cell temperature is 13 °C.
6.4 Fault information (ALM_INFO) ID: 0x07F4
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The alarm message is sent by event trigger. When there is an alarm, BMS sends the message periodically. If there is no alarm
message, it will not be sent.When multiple alarms occur at the same time, the alarm number will be displayed circularly on the
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instrument interface, up to 4 alarm numbers can be displayed circularly.The alarm number is shown in the order of alarm occurrence
as priority. The specific format is as follows:
Alarm no.
1
parameter
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Start bit
0
A length of The scope
2
of
0~3
The
resolution of
1
MS
The offset
0
unit note
MS
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The alarm level
2 Cell undervoltage 2 2 0~3 1 0
3 Total voltage overvoltage 4 2 0~3 1 0
Total voltage undervoltage
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4 6 2 0~3 1 0
5 Cell voltage difference 8 2 0~3 1 0
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6 Discharge overcurrent 10 2 0~3 1 0
7 Chaeging overcurrent 12 2 0~3 1 0
8 Temp too high 14 2 0~3 1 0
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9 Temp too low 16 2 0~3 1 0
10 Excessive temp difference 18 2 0~3 1 0
11 difference
SOC tooislow
too large 20 2 0~3 1 0
12 Insulation too low 22 2 0~3 1 0
13 High voltage interlock fault 24 2 0~3 1 0
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14 External communice fail 26 2 0~3 1 0
15 Internal communicate fail 28 2 0~3 1 0
Alarm level: 0 cfoormmunicatio
no alarm, 1n for serious alarm, 2 for important alarm, 3 for general alarm
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07F4 43 00 20 00 XX XX XX XX
Represents: monomer overpressure, level 3 alarm;Total voltage undervoltage, level 1 alarm;Too low SOC, level 2 alarm.
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7 Test cases
7.1 Normal state
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Normal state only displays SOC, voltage value, hour meter and other information.In normal state, only battery status message, cell
voltage message and cell temperature message are sent, and no alarm message is sent.
CANJD data Data meaning The instrument shows
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0x02F4 13 01 D7 11 33 XX 64 00 Voltage 27.5V, current The main interface displays voltage
of 2.75, SOC display of 51%, battery
BM 56.7A, SOC51%, discharge
time 100h
capacity of 2 cells, and current not
displayed
the current is not displayed
7. 2 Low battery
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When a low battery alarm occurs(SOC>=20%), the main page does not display voltage, but displays the current alarm
number. If it is a single unit alarm, the hour meter displays the corresponding unit number for the single unit alarm
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CANJD data Data meaning The instrument shows
0x02F4 El 00 8A 10 10 XX XX XX Voltage 22.5V, current
The main page displays alarm
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23.4 A, SOC 16% number 11, while the "AL"
symbol flashes, SOC displays
0x07F4 00 00 30 00 XX XX XX XX SOC 3 level alarm 16%, battery cells are 1,
and current is not displayed
7.3 Excessive and low monomer voltage
MS
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CANJD data Data meaning The instrument shows
0x04F4 8C 0A 05 92 09 08 XX XX
The main page displays
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Maximum unit voltage 2700mV,
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corresponding to unit number 5;alarm numbers 1 and 2 in
minimum unit voltage 2450mV a loop, while the "AL"
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corresponding to unit number 8 symbol flashes. Unit
numbers 5 and 8
corresponding to the
0x07F4 OF 00 00 00 XX XX XX XX Cell overvoltage level 3 alarm alarm displayed at the
hour meter
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Cell undervoltage level 3 alarm
7.4 Cell temperature is too high and too low
CANJD data Data meaning The instrument shows
0x05F4 48 06 2F 01 3F XX XX XX
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Maximum cell temp is 22 ° The main page displays
C, corresponding to unit alarm numbers 8 and 9 in a
number 6 loop, while the "AL"
Minimum cell temp is -3 ° symbol flashes. Unit
C, corresponding to unit numbers 6 and 1
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number 1. The average cell corresponding to the alarm
temp is 13 ° C displayed at the hour
0x07F4 00 CO 03 00 XX XX XX X iscell-3°C, corresponding cell meter
High temp,level 3 alarm
X cell Low temp,level
number is 1.Average3 alarm
cell
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level 3 alarmis 13°C
temperature
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The version VI. 02 Effective date 20190428
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