What practical problems can CAN communication solve?

[gavinray]

Hi everyone,

I have recently been studying CAN communication, especially its applications in automotive and industrial automation. I understand that CAN bus, as a reliable communication protocol, is widely used in systems that require real-time data exchange and distributed control. But I would like to learn more about what practical problems CAN communication can solve, specifically?

For example:

In multi-node systems, how does CAN simplify system integration and reduce wiring complexity?

What types of problems can the error detection and arbitration mechanism of the CAN protocol solve in practical applications?

How does CAN communication ensure reliability in high-noise environments?

Everyone is welcome to share their experiences and insights, especially if you have used CAN communication in actual projects. I am particularly interested in what specific problems it solves in different fields (such as automotive, industrial automation, medical devices, etc.).

Thank you!

 

[cupoftea]

Hi,
CAN isnt really anything special. Its just a type of differential signalling method.
The signal is sent not on wire with a ground return.
-But is sent as two opposing signals...the difference between them is the signal you want.
And the thing that receives this signal has to subtract one of the signals from the other, (to get the wanted signal) so noise that is common to both signals (it most often is common to both received wires), is cancelled out.

Thats about all there is to it.
Ie, the way it receives the signal has the effect of cancelling out the noise on the cable.

I suppose CAN is cheap, because it does it without needing a positive and a negative voltage supply.

It isnt by any means the most noise resilient of communications.

I guess its cheap differential signalling, with lots of silicon chip offerings for CAN receivers and senders.

 

[std_match]

Thats about all there is to it.
Ie, the way it receives the signal has the effect of cancelling out the noise on the cable.

It is better than that. CAN has mandatory CRC error checking and automatic retransmission.

 

[KlausST]

Hi,

Practical problems may be solved by CAN-bus:
* reduced wiring harness
* and thus reduced EMI, less wiring effort, less cable cost ...

Klaus

 

[cupoftea]

yes as the above says, its " daisy chain", so the same wire pair for multiple things.
Of course, that isnt particular to CAN only.
And yes, mandatory error checking CRC and auto retransmission....again, things extant in many other comms methods.
There are many other much more noise resilient diff signalling methods than CAN.

 

[KlausST]

Hi,

I would not call it "daisy chain".
I call it "parallel", since all connections are made in parallel.

***

A daisy chain usually has a "bus input" and a "bus output", where the output of one device goes to the input of the next device .. and so on.
Daisy chaining means the devices (data) are connected in series.
Like on an SPI example:
SPI_MASTER MOSI] --> [MOSI Slave1 MISO] --> [MOSI Slave2 MISO] --> [MOSI Slave3 MISO] --> [MISO Master
In this SPI example: all /SS are in parallel, all SCK are in parallel, just the data is in series.

Klaus

 

[FvM]

CAN bus is an automotive protocol standard. https://en.m.wikipedia.org/wiki/CAN_bus

Although end terminated linear ("partyline") bus is the preferred topology, lower speed implementations (<= 125 kbps) can use star and multi-star topology.