6. Communication

6.1. CAN

foxBMS 2 supports communication with other high level devices (e.g., the VCU) through CAN.

6.1.1. DBC File

These files describe the CAN interface used by foxBMS 2. The .dbc-file has been created using PCAN Symbol Editor Version 6.5.2 from symbol file Version 6.0.

The .dbc-file and .sym-file are located in tools/dbc.

6.1.1.1. Supported CAN Messages

6.1.1.1.1. Insulation Measurement Device

ID	Name	Implementation file
022h	IMD_BenderIso165c_Request	can_cbs_tx_imd_bender-iso165c-request.c
023h	IMD_BenderIso165c_Response	can_cbs_rx_imd_bender-iso165c-response.c
037h	IMD_BenderIso165c_Info	can_cbs_rx_imd_bender-iso165c-info.c

6.1.1.1.2. Crash Dump

ID	Name	Comment	Implementation file
0FFh	f_CrashDump	Fatal error information	can_cbs_tx_f_crash-dump.c

6.1.1.1.3. BMS Status

ID	Name	Comment	Implementation file
210h	f_BmsStateRequest	Requests specific BMS behavior and gives the BMS required information from the higher-level control unit	can_cbs_rx_f_bms-state-request.c
220h	f_BmsState	Message contains general BMS state information	can_cbs_tx_f_bms-state.c
221h	f_BmsStateDetails	Details on flags transmitted by the ‘BmsState’ message	can_cbs_tx_f_bms-state-details.c
222h	f_BmsFatalError	Message contains the fatal error code	can_cbs_tx_f_fatal-error.c

6.1.1.1.4. State Machine Information

ID	Name	Comment	Implementation file
219h	f_SystemState	Message contains the state of our System state machine	can_cbs_tx_f_sys-state.c

6.1.1.1.5. Pack Information

ID	Name	Comment	Implementation file
230h	f_PackMinMaxCellTemperature		can_cbs_tx_f_pack-minimum-maximum-values.c
231h	f_PackMinMaxCellVoltage		can_cbs_tx_f_pack-minimum-maximum-values.c
232h	f_PackLimits	Electrical limit information	can_cbs_tx_f_pack-limits.c
233h	f_PackValuesP0		can_cbs_tx_f_pack-values-p0.c
234h	f_PackValuesP1		can_cbs_tx_f_pack-values-p1.c
235h	f_PackStateEstimation		can_cbs_tx_f_pack-state-estimation.c

6.1.1.1.6. String Information

ID	Name	Comment	Implementation file
240h	f_StringState	Message contains string related error and warning flags	can_cbs_tx_f_string-state.c
241h	f_StringMinMaxCellTemperature	Message contains minimum and maximum cell temperature values and their indices of respective string	can_cbs_tx_f_string-minimum-maximum-values.c
242h	f_StringMinMaxCellVoltage	Message contains minimum and maximum cell voltage values and their indices of respective string	can_cbs_tx_f_string-minimum-maximum-values.c
243h	f_StringValuesP0	Message contains string voltage, current and power	can_cbs_tx_f_string-values-p0.c
244h	f_StringValuesP1	Message contains energy counting value	can_cbs_tx_f_string-values-p1.c
245h	f_StringStateEstimation	Message contains SOC, SOE and SOH state estimations	can_cbs_tx_f_string-state-estimation.c

6.1.1.1.7. Cell Information

ID	Name	Comment	Implementation file
250h	f_CellVoltages	Cell voltage measurement data	can_cbs_tx_f_cell-voltages.c
260h	f_CellTemperatures	Cell temperature measurement data	can_cbs_tx_f_cell-temperatures.c
270h	AFE_CellVoltages	Cell voltage measurement data	can_cbs_rx_afe_cell-voltages.c
280h	AFE_CellTemperatures	Cell temperature measurement data	can_cbs_rx_afe_cell-temperatures.c

6.1.1.1.8. Debug

ID	Name	Comment	Implementation file
300h	f_Debug	Reserved - for debug/development purpose only	can_cbs_rx_f_debug.c
301h	f_DebugResponse	Responses to the ‘Debug’ message	can_cbs_tx_f_debug-response.c
302h	f_DebugUnsupportedMultiplexerVal		can_cbs_tx_f_debug-unsupported-multiplexer-values.c
303h	f_DebugBuildConfiguration	Contains the build configuration	can_cbs_tx_f_debug-build-configuration.c
304h	f_DebugIdentifyHardware	Contains the hardware identifications	can_cbs_tx_f_debug-identify-hardware.c

6.1.1.1.9. Current Sensor

ID	Name	Comment	Implementation file
3C2h	CS_LemCab500String0	LEM Current Sensor	can_cbs_rx_cs_lem-cab500.c
521h	CS_IsabellenhuetteIvtString0Curr	Current sensor string 0: current	can_cbs_rx_cs_isabellenhuette-ivt-s.c
522h	CS_IsabellenhuetteIvtString0V1	Current sensor string 0: voltage 1	can_cbs_rx_cs_isabellenhuette-ivt-s.c
523h	CS_IsabellenhuetteIvtString0V2	Current sensor string 0: voltage 2	can_cbs_rx_cs_isabellenhuette-ivt-s.c
524h	CS_IsabellenhuetteIvtString0V3	Current sensor string 0: voltage 3	can_cbs_rx_cs_isabellenhuette-ivt-s.c
525h	CS_IsabellenhuetteIvtString0Temp	Current sensor string 0: temperature	can_cbs_rx_cs_isabellenhuette-ivt-s.c
526h	CS_IsabellenhuetteIvtString0Pwr	Current sensor string 0: power	can_cbs_rx_cs_isabellenhuette-ivt-s.c
527h	CS_IsabellenhuetteIvtString0Cc	Current sensor string 0: coulomb counting	can_cbs_rx_cs_isabellenhuette-ivt-s.c
528h	CS_IsabellenhuetteIvtString0Ec	Current sensor string 0: energy counting	can_cbs_rx_cs_isabellenhuette-ivt-s.c

6.1.1.1.10. Aerosol Sensor

ID	Name	Comment	Implementation file
3C4h	AS_HoneywellBas6cX00		can_cbs_rx_as_honeywell-bas6c-x00.c

6.1.2. CAN TX Behavior

6.1.2.1. Cyclic Messages

The cyclic transmit list is configured in can_txMessages[] in src/app/driver/config/can_cfg_tx_cyclic.c.

The cyclic messages are not sent immediately after startup. Periodic TX is globally gated by can_state.periodicEnable in CAN_MainFunction():

If periodicEnable == false, no cyclic TX is executed.
If periodicEnable == true, CAN_PeriodicTransmit() sends all configured cyclic messages according to period and phase.

This gate is enabled during SYS initialization. After that point, cyclic transmission runs continuously.

The BMS cyclically transmits these messages:

f_SysState
f_BmsState
f_BmsStateDetails
f_CellVoltages
f_CellTemperatures
f_PackLimits
f_PackMinimumMaximumVoltage
f_PackMinimumMaximumTemp
f_PackStateEstimation
f_PackValuesP0
f_PackValuesP1
f_StringState
f_StringMinimumMaximumVoltage
f_StringMinimumMaximumTemp
f_StringStateEstimation
f_StringValuesP0
f_StringValuesP1

6.1.2.2. On-demand Messages

The following transmitted messages are sent on request, not cyclically:

f_DebugResponse, including requested payload variants such as version information, commit hash, RTC time, boot timestamp and uptime.
f_DebugBuildConfiguration.
f_DebugIdentifyHardware.
f_DebugUnsupportedMultiplexerValues when an unsupported debug multiplexer value is received.

These responses are triggered by received f_Debug frames in CANRX_Debug().

6.1.2.3. Further Asynchronous Transmitted Messages

Some asynchronous TX messages are event-driven and therefore neither cyclic nor request/response from f_Debug:

f_BmsState is additionally sent asynchronously when BMS state or substate changes (CANTX_TransmitBmsState()).
f_BmsFatalError is sent by the diagnosis module when fatal errors are set/cleared and periodically resent while active.
f_CrashDump is sent on detected stack overflow.

6.2. Ethernet

Additionally to to CAN communication an ethernet communication interface is provided. Currently plain TCP/IP is supported for user defined application tasks. These tasks can be placed in ethernet.c. As an example and for testing purposes an echo server is implemented there. More details can be found in Ethernet.