Deciding Between 11-bit and 29-bit Identifiers in CAN

[Kittu20]

I'm currently exploring the specifications of the CAN (Control Area Network) protocol. I'm trying to understand decision to select an 11-bit identifier or a 29-bit identifier.

From what I've gathered, if our application involves a limited number of unique messages communicating on the CAN bus, the 11-bit identifier might suffice. It offers up to 2,048 (2^11) unique message IDs.

Considering this, I'm interested to hear from the community about their experiences. What factors did you consider when choosing between the two identifier lengths

 

[KlausST]

Hi,

First: I`m not really experienced with CAN.

I don´t know your application nor it´s requirements, nor all your CAN devices.

Thus I´d prefer 11 bit identifier, because it is the more "standard" one. Every CAN device should be able to work with 11 bit ID. But not every CAN device can work with 29 bit ID.

But for sure if your application requires (because there is an existing CAN system you have to be compatible with) 29 bit ID, then you have to use it.

If there is no existing system: Then just decide whether you are fine with 11 bits then use it. Just write down how you want to "code / manage" your IDs then decide if you are good with 11 bits or you need to chose 29 bits. In most cases I think 11 bits (2048 different IDs) will do.

Klaus