Redundancy in CAN Architecture

Komal Sharma

Other Parts Discussed in Thread: SN65HVD257

Hi,

I am working on a CAN bus network based project, where I need to focus on the areas wherever redundancy for high availability is possible (all areas for example communication availability, power supply etc are to be considered). I studied few papers stating about media redundancy... Please help me by suggesting the right approach towards the problem.

over 5 years ago

0 Max Robertson over 5 years ago

TI__Guru 62910 points

Komal,

A common approach is to use two separate CAN buses, one "primary" and one "secondary" that is used in the case of a failure of the primary bus. You can find an example implementation on our evaluation module for the SN65HVD257 chip (link: www.ti.com/.../sllu172.pdf). This device is useful in this application since it has a "fault" output indicator that is able to report certain CAN bus faults. This implementation also shows some external logic circuits that could be used to interface both transceivers to a common CAN port on an MCU.

Thanks,
Max

0 Komal Sharma over 5 years ago in reply to Max Robertson

Intellectual 395 points

Thanks a lot sir for your guidance. I am not able to navigate to the link u mentioned above. It is displaying an error message. Could you please send the link again.

0 Max Robertson over 5 years ago in reply to Komal Sharma

TI__Guru 62910 points

Sorry about that. Let's see if it works this time:

www.ti.com/.../sllu172.pdf

Regards,
Max

0 Komal Sharma over 5 years ago in reply to Max Robertson

Intellectual 395 points

Thanks Sir. Also, Can you throw some light on "The SN65HVD257 CAN EVM also provides PCB footprints for different bus terminations, bus filtering, and protection concepts." What is the significance of PCB footprints and what is bus filtering? Could you please elaborate.

0 Max Robertson over 5 years ago in reply to Komal Sharma

TI__Guru 62910 points

Komal,

That just means that there are a lot of different pads on the PCB for installing different components. Some people use filters on the CAN line to improve the RF noise immunity and emissions (since there are strict requirements on these in automotive applications). Filter components are generally intended to attenuate high-frequency noise on the CAN lines. This is sometimes done simply with capacitors (for example, 100 pF from CANH to ground and from CANL to ground) or could be done with something like a common mode choke (which is placed in series with the CAN lines, providing a high impedance at high frequencies to common-mode components of the CAN signal while providing a low impedance to the normal differential-mode signal).

Max

0 Komal Sharma over 5 years ago in reply to Max Robertson

Intellectual 395 points

Thanks a lot sir!

Interface

Interface forum

Redundancy in CAN Architecture