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Documentation of CAN messages

CMM-2CH and CMM-3CH can be controlled via CAN-FD. Each measurement channel has its own microcontroller. The nominal baudrate is 1 MBit/s, the data baudrate is 4 MBit/s. A DBC file is available on the download page.

Structure of CAN-IDs

The CAN IDs are build with the following scheme.

Bit

Mask

Content

Comment

The highest value of board (0xFF) and channel (0xF) is used as broadcast. For example the ID 0x 0 00 4D 01 F is the command "SetOnOff" (= 0x01) for all channels on board 1.

Physical values are always transmitted as float (32 Bit / Single Precision / LSB first) and in the base unit (V / A / sec / °C / ... ).

Get-ID and Response-ID are the same, because the already differ in the direction bit 28. The command values in the following table include the direction bit, to make this clear.

Set-ID

Get-ID

Response-ID

Command

DLC

Data

Code

Description

Name

Value

Physical values are always transmitted as float (32 Bit / Single Precision / LSB first) and in the base unit (V / A / sec / °C / ... ).

Command-ID

Name

DLC

Data

Documentation of CAN messages

Structure of CAN-IDs

The CAN IDs are build with the following scheme.

Bit

Mask

Content

Comment

The highest value of board (0xFF) and channel (0xF) is used as broadcast. For example the ID 0x 0 00 4D 01 F is the command "SetOnOff" (= 0x01) for all channels on board 1.

Physical values are always transmitted as float (32 Bit / Single Precision / LSB first) and in the base unit (V / A / sec / °C / ... ).

Get-ID and Response-ID are the same, because the already differ in the direction bit 28. The command values in the following table include the direction bit, to make this clear.

Set-ID

Get-ID

Response-ID

Command

DLC

Data

Code

Description

Name

Value

Physical values are always transmitted as float (32 Bit / Single Precision / LSB first) and in the base unit (V / A / sec / °C / ... ).

Command-ID

Name

DLC

Data

0x001

0x041

0x141

OnOff

OnOff [0/1] (U1)

0x002

OnOffSelected

EnableMask_Board (U8)

0x003

0x043

0x143

MinRange

MinRange (U8)

0x004

0x044

0x144

MinMaxAvg

CurrentMin [A] (float), CurrentAvg [A] (float), CurrentMax [A] (float),

VoltageDropMax [V] (float), NoOfSamples (U32), RangeMin (U8), RangeMax (U8)

0x005

0x045

0x145

ChannelConfig

OnOffDefaultValue [0/1] (U1), MeasuredValuesInterval [sec] (float)

0x006

0x046

0x146

CanConfig

TxFrameFormat [Enum] (U8), NominalBaudrate [Enum] (U8), DataBaudrate [Enum] (U8)

0x007

0x047

0x147

LegacyConfig

LocalId (U32), LocalIdIsExt (U1),RemoteId (U32), RemoteIdIsExt (U1)

LegacyCyclicId (U32), LegacyCyclicIdIsExt (U1), LegacyCyclicMessageEnable (U1)

0x048

0x148

Version

HardwareType (U8), FirmwareVersion (U16), CompileTimestamp (U32),

WarningRegister (U16), HardwareVersion (U8)

0x049

0x149

SerialNumber

SerialNumber (String 12 Bytes)

0x00A

RestoreDefault

0x00D

0x04D

0x14D

DisableCalibration

DisableCalibration [0/1] (U1)

Documentation of CAN messages

Structure of CAN-IDs

Documentation of CAN messages

Structure of CAN-IDs

List of CAN-Commands

CAN-IDs to set and get register style values

Status codes

Values in WarningRegister

Cyclic CAN-IDs uC -> PC