Revision as of 12:01, 25 June 2025

The CAN ID is a number to identify messages and modules (axis and IO) on the CAN bus. In the CPRCANv2 protocol specific number ranges are reserved for specific modules. The CAN ID is assigned to a module via the yellow selector wheel at the top of DIN rail modules or via solder connections on igus ReBeL joints.

CPRCANv2 CAN IDs can be described in 3 different ways: by the number of the selector wheel (0-9), in hexadecimal (e.g. 0x10) or decimal (e.g. 16). In configuration files generally the decimal representation is used, while the user interface usually uses the hexadecimal representation for readability.

Axis modules

The following CAN IDs are available for axis modules.

Selector	Decimal	Hex	Note
0	16	0x10	A1
1	24	0x18	available
2	32	0x20	A2
3	40	0x28	available
4	48	0x30	A3
5	56	0x38	available
6	64	0x40	A4
7	72	0x48	available
8	80	0x50	A5
9	88	0x58	A6 on control cabinets, otherwise available
n/a	96	0x60	A6 on igus ReBeL

As a rule of thumb for robot axes (not external axes and note the exception for A6, see the table above):

The selector wheel starts at 0, then increases in steps of 2 (e.g. A1 = 0, A2 = 2, A3 = 4,...)
Hexadecimal values start increase in steps of 0x10 (e.g. A1 = 0x10, A2 = 0x20, A3 = 0x30,...)
Decimal values start at 16 and increase in steps of 16 (e.g. A1 = 16, A2 = 32,...)

Note that there is a maximum of 6 robot axes, 3 external axes, 4 mobile platform axes and 3 tool axes (currently not available).

Digital IO Modules

Digital IO modules use a similar scheme but a different offset.

Selector	Decimal	Hex	Note
0	112	0x70	IO 1
1	120	0x78	available
2	128	0x80	IO 2
3	136	0x88	available
4	144	0x90	IO 3
5	152	0x98	available
6	160	0xA0	IO 4
7	168	0xA8	available
8	176	0xB0	IO 5
9	184	0xB8	available

Note that there is a maximum of 5 IO modules, the 5th module only supports 4 inputs and outputs. When adding IO modules the software automatically assigns an ID depending on the robot type but generally in the scheme shown above. It can be changed in the project configuration file but this is not recommended.