CAN Protocol

This page describes the CAN protocol the user can use to interact with the motor controller. This includes TX and RX. The Steinmetz motor controller uses Standard CAN IDs. In future versions, the ability to customize the communication protocol will be possible.

Note

By default all words are packed as little-endian.

TX (Emitted from Motor Controller)

Summary

TX CAN Messages

CAN ID	CAN Message Name	Brief Description
0x012	Resolver	Raw data from resolver to digital converter.
0x016	State ID	The state of the state machine see: State Machine
0x01c	EEPROM Set Response	Response/ACK when writing to EEPROM.
0x01d	EEPROM Get Response	Response/ACK when reading from EEPROM.
0x020	DQ Currents	Computed DQ current data.
0x021	PWM Duty Cycles	Phase A, B and C switching duty cycles.
0x022	DQ PID Integral	Computed integral term for DQ PID loop.
0x025	Electrical Angle	Processed information on Electrical Angle
0x029	Switching Misc Data	Extra telemetry data from switching.
0x306	GPIO State	External GPIO Data
0x310-0x31B	Temperature Data	Individual Thermistor Data
0x31D	Fault Trigger NP Cap Voltages	NP cap voltage readings that triggered latched overvoltage faults. Only sent when one of those faults is latched.
0x31E	Fault Trigger Current/Temp	Current and temperature readings that triggered latched current/overtemp faults. Only sent when a relevant fault is latched.
0x31F	Fault Trigger HV Undervoltage	HV bus voltage reading that triggered the HV undervoltage fault. Only sent when that fault is latched.
0x320-0x324	Current and Voltage Sensor Readings	Phase Current and Voltage Sense Readings

0x012 (Resolver)

Resolver Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
POSITION	Resolver Position in Degrees	100	u16
VELOCITY	Resolver Rotational Velocity in Degrees per second	100	i32
FAULT	The Fault bits in the resolver to digital converter. The resolver used is the AD2S1210, see AD2S1210 datasheet, for detailed description of the fault register.	N/A	u8

0x016 (State ID)

State ID Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
STATE	State ID. See State Machine for details	N/A	u8
OVC	Phase current magnitude exceeded configured overcurrent threshold	N/A	N/A
ISNS_LOC	Internal communication issue to current sense ADC	N/A	N/A
OVT	Transistor temperature exceeded configured overtemperature threshold	N/A	N/A
TSNS_LOC	Internal communication issue to temperature sense ADC	N/A	N/A
HVN_NP_OV	Voltage across capacitor from HV- to neutral point exceeded configured threshold, indicates risk of FET damage	N/A	N/A
NP_HVP_OV	Voltage across capacitor from neutral point to HV+ exceeded configured threshold, indicates risk of FET damage	N/A	N/A
RDC_FLT	The resolver has a fault, specific details in 0x012 (Resolver)	N/A	N/A
HVIL_FLT	One or more HV connectors are not properly seated. This check can be enabled/disabled in the EEPROM Configuration	N/A	N/A
DC_PH_FLT	The controller thinks a motor phase is not properly connected to the motor controller. The relevant thresholds can be modified in the EEPROM Configuration	N/A	N/A
HV_UV_FLT	Undervoltage on the HV bus. The threshold can be altered in the EEPROM Configuration	N/A	N/A
RESERVED	Reserved	N/A	f32
MESSAGE HEARTBEAT TIMESTAMP	Milliseconds since last heartbeat. Saturates at 65535ms.	1	u16

Note

When a fault occurs, the corresponding bit will latch high. The bit will not clear until a Clear Faults command is issued via the 0x019 (Command Packet).

Additionally, while a fault bit is latched high, the motor controller will transmit packets indicating the worst-case value seen while the fault was latched (see 0x31D (Fault Trigger NP Cap Voltages), 0x31E (Fault Trigger Current/Temp), 0x31F (Fault Trigger HV Undervoltage)).

0x01c (EEPROM Set Response)

EEPROM Set Response Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
FIELD	Returns the field that was attempted to be written to. If the request was reset to default this field will be 0xFF.	N/A	u8
RETURN CODE	A RETURN CODE = 0x00 indicates success. Typical failure codes: 0xFF - The motor controller is not in a safe state to alter configs (must be ReadyToSwitch or Faulted) 0xFE - Unrecognized config key 0xFD - The value requires a special unlock to modify 0xFC - Value is invalid or out of bounds	N/A	u8

0x01d (EEPROM Get Response)

EEPROM Get Response Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
FIELD	Returns the ID of the field that was requested	N/A	u8
DATA	Returns the data from the field.	N/A	field-dependent (f32 default)

0x020 (DQ Currents)

DQ Currents Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
ID	Current in the D axis in amperes (signed)	1000	i24
IQ	Current in the Q axis in amperes (signed)	1000	i24
TORQUE	Estimated Torque being delivered based on Torque Constant and Q current. (Newton-Metres). (Currently this saturates, will be improved in next firmware revision, use IQ for a better torque estimation)	1000	i24

0x021 (PWM Duty Cycles)

PWM Duty Cycles Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
PHASE_A_HIGH	Percentage of switching cycle for which phase A is in the high switching state (connected to HV+)	255	u8
PHASE_A_MID	Percentage of switching cycle for which phase A is in the mid switching state (connected to inverter’s neutral point)	255	u8
PHASE_B_HIGH	Percentage of switching cycle for which phase B is in the high switching state (connected to HV+)	255	u8
PHASE_B_MID	Percentage of switching cycle for which phase B is in the mid switching state (connected to inverter’s neutral point)	255	u8
PHASE_C_HIGH	Percentage of switching cycle for which phase C is in the high switching state (connected to HV+)	255	u8
PHASE_C_MID	Percentage of switching cycle for which phase C is in the mid switching state (connected to inverter’s neutral point)	255	u8

As all of the percentages must add up to 100%, the values for PHASE_A_LOW, PHASE_B_LOW, and PHASE_C_LOW can be calculated. For example, using pre-scaling values, PHASE_A_LOW = 255 - PHASE_A_HIGH - PHASE_A_MID

0x022 (DQ PID Integral + DC Current estimate)

DQ PID Integral Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
D_INTEGRAL	The accumulated integral term for the D side of the PID loop (in Volts)	10	i16
Q_INTEGRAL	The accumulated integral term for the Q side of the PID loop (in Volts)	10	i16
DC_BUS_CURRENT	Estimated DC link current draw in Amperes	1000	i24

0x025 (Electrical Angle)

Electrical Angle Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
ELECTRICAL_ANGLE	The electrical angle of the motor. Used in the DQZ transforms. Stored as degrees.	100	i32
ELECTRICAL_VELOCITY	The electrical velocity of the motor. Used in the DQZ transforms. Stored in degrees per seconds.	100	i32

0x029 (Switching Misc Data)

Switching Misc Data

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
RESERVED_DEBUG_DATA_A
RESERVED_DEBUG_DATA_B

0x306 (GPIO State)

GPIO State

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
GPIO_DATA	To be implemented	N/A	N/A

0x310-0x31B (Temperature Data)

Indexed as (0x310 + n) where n is the nth group of temperature readings.

Temperature Data

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
TEMPERATURE_1	Temperature reading from 1 thermistor in Celsius	100	i16
TEMPERATURE_2	Temperature reading from 1 thermistor in Celsius	100	i16
TEMPERATURE_3	Temperature reading from 1 thermistor in Celsius	100	i16
TEMPERATURE_4	Temperature reading from 1 thermistor in Celsius	100	i16

0x31C (External RTD interface)

Indexed as (0x310 + n) where n is the nth group of temperature readings.

Temperature Data

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
EXT_RTD_VAL	Temperature reading from external PT1000 RTD in Celsius. Can alternately report resistance – configurable in EEPROM Configuration.	100	i32

0x31D (Fault Trigger NP Cap Voltages)

Only transmitted when at least one NP cap overvoltage fault (HVN_NP_OV or NP_HVP_OV in 0x016 (State ID)) is latched. Fields for faults that have not triggered are reported as 0.

Fault Trigger NP Cap Voltages Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
GND_TO_NP_TRIGGER_V	Highest voltage across the capacitor from GND to neutral point that triggered the HVN_NP_OV fault, in Volts. Corresponds to V_NEUTRAL_POINT in 0x323 (Voltage Sense).	1,000,000	i32
NP_TO_DCBUS_TRIGGER_V	Highest voltage across the capacitor from neutral point to HV+ that triggered the NP_HVP_OV fault, in Volts. Corresponds to V_BUS - V_NEUTRAL_POINT in 0x323 (Voltage Sense).	1,000,000	i32

0x31E (Fault Trigger Current/Temp)

Only transmitted when at either of the OVC or OVT faults are latched in 0x016 (State ID). Fields for faults that have not triggered are reported as 0.

Fault Trigger Current/Temp Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
OVERTEMP_TRIGGER_C	Highest transistor temperature that triggered the OVT fault, in Celsius.	100	i16
OVERCURRENT_TRIGGER_A	Highest magnitude phase current that triggered the OVC fault, in Amperes.	1,000,000	i32

0x31F (Fault Trigger HV Undervoltage)

Only transmitted when the HV undervoltage fault (HV_UV_FLT in 0x016 (State ID)) is latched.

Fault Trigger HV Undervoltage Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
HV_UV_TRIGGER_V	Lowest HV bus voltage that triggered the HV_UV_FLT fault, in Volts. Corresponds to V_BUS in 0x323 (Voltage Sense).	1,000,000	i32

0x320 (Current Sense Phase C)

Current Sense Phase C

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
I_COARSE_C	Coarse current readings from Phase C in Amperes.	1,000,000	i32
I_FINE_C	Fine current readings from Phase C in Amperes.	1,000,000	i32

0x321 (Current Sense Phase B)

Current Sense Phase B

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
I_COARSE_B	Coarse current readings from Phase B in Amperes.	1,000,000	i32
I_FINE_B	Fine current readings from Phase B in Amperes.	1,000,000	i32

0x322 (Current Sense Phase A)

Current Sense Phase A

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
I_COARSE_A	Coarse current readings from Phase A in Amperes.	1,000,000	i32
I_FINE_A	Fine current readings from Phase A in Amperes.	1,000,000	i32

0x323 (Voltage Sense)

Voltage Sense

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
V_NEUTRAL_POINT	Voltage from V- to Neutral Point in Volts.	1,000,000	i32
V_BUS	Voltage from V- to V+ in Volts.	1,000,000	i32

0x324 (Current Sense ADC Debug)

Current Sense ADC Debug

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
RESERVED		N/A

RX (Received by Motor Controller)

Summary

RX CAN Messages

CAN ID	CAN Message Name	Brief Description
0x019	Command Packet	Command packet. Used to traverse state machine and command torque/speed.
0x01a	EEPROM Set Parameter	Write parameter to EEPROM.
0x01b	EEPROM Get Parameter	Read parameter to EEPROM.

0x019 (Command Packet)

Command Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
COMMAND	Command sent from user. See Command Table below.	N/A	u8
DATA	The data supplement used with the command packet. i.e in torque control the desired torque.	0.1 Nm (torque control) or 1 degree per second (velocity control)	i32

Command Table

Command ID	Command Description	Data Description	Data Scaling (Divide by X to get real value)
0x00	DISABLE. This tells the motor controller to enter a disable state. This should take the motor controller into the ReadyToSwitch state.	DATA unused, leave as 0x00	N/A
0x01	Enable (Torque Control). This instructs the motor controller to go into torque control mode. It will transition to ActivelySwitching and attempt to drive a desired torque.	DATA is desired torque in Newton-Metres	1
0x02	Enable (Velocity Control). This instructs the motor controller to go into velocity control mode. It will transition to ActivelySwitching and attempt to drive a desired velocity.	DATA is desired velocity in degrees per second.	1
0xFF	Clear Faults. Attempt to clear non-latching faults of motor controller. See State Machine	DATA unused, leave as 0x00	N/A

0x01a (EEPROM Set Parameter)

EEPROM Set Parameter Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
FIELD	ID of the desired parameter to modify	N/A	u8
DATA	Data to be written to EEPROM parameter.	N/A	field-dependent, default f32
RESERVED	Reserved data, leave as 0x00.	N/A	N/A

0x01b (EEPROM Get Parameter)

EEPROM Set Parameter Packet

Data Word	Description	Scaling (Divide by X to get real value)	Datatype
FIELD	ID of the desired parameter to read	N/A	u8
RESERVED	Reserved data, leave as 0x00.	N/A	N/A