Low-Speed CANBUS

I need to receive CAN BUS in a Fiat Ducato. This car uses a Low-Speed CAN Bus for information about the state of door locks. The key voltage difference is that Low-Speed CAN (LS-CAN) operates with a larger differential voltage (up to 4V), while High-Speed CAN (HS-CAN) uses a smaller differential voltage (around 2V) during the dominant state.

Can the CAN Bus Breakout Board help me with this task? Or is it only capable of vHigh-Speed CAN Bus?

Best Regards
Maettu

Welcome!

Seeed Studio XIAO CAN Bus Expansion Board - CAN bus, MCP2515 controller, SN65HVD230 transceiver chip - Seeed Studio?

Yep, I read the Wiki more than just once, but I did not find any information about Low Speed Can Bus in particular, but perhaps I missed something? I could, of course, simply buy a board and try it out, but I fear damaging the cars canbus…

Hello Christopher
Thank you for the Product suggestions. I looked at them, but none of them claims to be able to read LOW-Speed CAN Bus Messages. Is this feature so unimportant that nobody cares, or does it work with any of these products anyway, so all my worries are unnecessary?

Do you expect theses products to work on a LOW-SPEED CAN Bus, or are your posts more like “have a look at these, maybe these are interesting for you”?

Best Regards
Matthias

1 Like

Buying a board and testing it could be a good way to learn, but it’s smart to be cautious about potentially damaging your car’s CAN bus.

Hi there,
From what I get it’s just the baud rate mostly, and the connections all use the same transceivers so the physical connection is standard.
" Low-Speed CAN is commonly used to control “comfort” devices in an automobile, such as seat adjustment, mirror adjustment, and door locking . It differs from High-Speed CAN in that the maximum baud rate is 125K and it utilizes CAN transceivers that offer fault-tolerant capability. "
from NI site I know the basic seeed unit can be used to monitor the bus and see what frames for codes is possible.
NI say’s
"Low-Speed CAN is commonly used to control “comfort” devices in an automobile, such as seat adjustment, mirror adjustment, and door locking. It differs from High-Speed CAN in that the maximum baud rate is 125K and it utilizes CAN transceivers that offer fault-tolerant capability. This enables the CAN bus to keep operating even if one of the wires is cut or short-circuited because it operates on relative changes in voltage, and thus provides a much higher level of safety. The transceiver solves many common and frequent wiring problems such as poor connectors, and also overcomes short circuits of either transmission wire to ground or battery voltage, or the other transmission wire. The transceiver resolves the fault situation without involvement of external hardware or software. On the detection of a fault, the transceiver switches to a one wire transmission mode and automatically switches back to differential mode if the fault is removed.

Special resistors are added to the circuitry for the proper operation of the fault-tolerant transceiver. The values of the resistors depend on the number of nodes and the resistance values per node. For guidelines on selecting the resistor, refer to Cabling Requirements for Low-Speed/Fault-Tolerant CAN.

USB to CAN Analyzer Adapter with USB Cable

plus the adapter for OBDII connection. All in all how bad do you want it is the question.
the software it comes with is pretty good I’m told it does what is needed in most cases.
YMMV
HTH
GL :slight_smile: PJ :v:

all the how to’s start with monitor the mirrors for the code to move them…LOL

Yes… I have never tried to use can so I don’t know… I know that some people may not know all the products which have been produced by seeed and sometime they do not come up I search results so I just sent them:… I didn’t go thru the data to see how f it had such a mode

Hi,

Low-Speed CAN and High-Speed CAN are not compatible because they are different in physical definition, just as you mentioned.

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019LzHSAU