CAN Bus protocol¶

CAN Commands to MC24¶

MC24 can receive commands from any CAN device. All CAN messages for MC24 follow the same structure, a string of bits divided in two groups:

Group	Name	Size	Description
1	CAN Id	4 bytes	CAN Id could be in standard (11-bits) or extended frame format (29-bits). If the CAN Id matches with the Id of a MC24 input filter (a type of CAN consumer), the message will be correctly read by the MC speed filter consumer. Otherwise it will be ignored.
2	Speed	4 bytes	Speed must be represented with a compressed 32-bit signed variable with little endian format. The values of this variable should be in the range [0 to maximum RPM (speed)] or [-maximum RPM to maximum RPM], this depends if users want to allow negative commands. Note Negative values command the opposite movement to positive ones. Therefore, the maximum value corresponds with the maximum speed and the maximum negative value corresponds with the maximum reversed speed.

Group

Name

Size

Description

CAN Id

4 bytes

CAN Id could be in standard (11-bits) or extended frame format (29-bits).

If the CAN Id matches with the Id of a MC24 input filter (a type of CAN consumer), the message will be correctly read by the MC speed filter consumer. Otherwise it will be ignored.

Speed

4 bytes

Speed must be represented with a compressed 32-bit signed variable with little endian format.

The values of this variable should be in the range [0 to maximum RPM (speed)] or [-maximum RPM to maximum RPM], this depends if users want to allow negative commands.

Note

Negative values command the opposite movement to positive ones.

Therefore, the maximum value corresponds with the maximum speed and the maximum negative value corresponds with the maximum reversed speed.

The parameter that is configured in the MC24 to receive these CAN commads is the CAN Id of Input filter producer, which has to be linked to the CAN Cmd consumer. To know more, read the CAN I/O - Input/Output section of the MC24 PDI Builder user manual.

An example for sending commands from Veronte Autopilot 1x to a MC24 unit is explained in the MC110/MC24 - Integration examples section of the 1x PDI Builder user manual.

Telemetry messages from MC24¶

Telemetry messages can be transmitted from the MC24 unit to provide information of interest to the user, such as the board temperature or the input command values.

CAN messages sent by MC24 have also the structure:

CAN Id: It can be in standard frame format (11-bits) or in extended frame format (29-bits). The CAN Id frame format will depend on the CAN protocol of the receiving device.
Variable: Users can send as telemetry the variable they want to know information about. All the variables available to be sent from the MC24 unit can be consulted in the Lists of Variables section of this manual.

The format in which these variables must be sent will depend on the CAN protocol of the device that will read the message.

Detailed information on how to build CAN messages can be consulted in the Custom Messages types - Input/Output section of the 1x PDI Builder user manual.