CAN BUS Speeds

[Brendan]

Hello,

Looking at an ECU upgrade over the next year, and I had a question on bus speeds for the S8 and CAN implementations. I would likely have PDU, Dash, Switch panel when I rewire - most of the options I've looked at are 1 MB/s bus speed. I will also be running a Teves MK60 ABS from a BMW E46 M3, and would like to read 4 x wheel speed, 2 x brake pressure, steering angle as they are all broadcast via CAN from the ABS. From what I've found, this utilizes a 500 KB/s bus speed.

I've done some playing around with SCal, looked through forums and manuals and can't seem to answer for myself. Would utilizing the different bus speeds be possible? Could I set CAN1 to run at 1MB and CAN2 to run at 500K? If not - has anyone had success with an emulator or adapter to convert bus speed between 500K & 1M?

Also - anyone else running this ABS successfully?

Thanks in advance,

Brendan

[pat]

Brendan,

the default speed for the CAN bus on an S8 when configured to "Custom CAN" is 1Mbps.

With regard to receiving wheel speeds etc across CAN, there is support for the 1Mbps Bosch Motorsport M4 ABS stream, but not for the 500kbit implementation. Furthermore there is no guarantee that the Teves unit will be using a similar protocol. It is not normally possible to run (say) Bosch M4 on one CAN bus and Custom CAN on the other - that might fall under the category of a feature request

Perhaps a more effective approach would be to keep the S8 just the way it is supposed to be and then to use a CAN bridge to allow information from the Teves 500kbit/s bus to be presented to the S8 on the 1Mbit/s bus and in an emulated Bosch M4 stream - so all you'de need to do is to enable reception of that stream and you'de get all the info you are after. Given that this comes from an E46 it is likely that we already have done something like this in the past and that therefore it would not take a long time to implement (essentially a cut down version of a full E46 integration bridge).

Hope this helps,

Pat.

[Brendan]

Hi Pat,

Do you have any experience with a CAN bridge that works well? I've seen a couple while browsing, but no personal experience. I do think having different CAN inputs being able to utilize different bus speeds (500 kBit or 1 MBit) and allow custom CAN on either would be a nice "enhancement request" to consider in the future, but probably not needed here if a bridge would work.

Regarding the Teves unit - I have some CAN / ARB id and conversion factor information, and I know that these have been used with other ECUs (Pectel and MoTec off the top of my head), so I guess it would be a question of whether I have (or you already have) all of the information required.

A more generic question - When doing a Custom CAN implementation - is that something I'd need you / Syvecs to generate the custom configuration for me, or is there any ability for the end-user to edit the configuration (CAN ARBID, conversion factors, etc..) to implement a CAN device?

Thanks for the help.

Brendan

[pat]

Hiya Brendan!

We produce a CAN bridge which we use for vehicle integration work and that seems to be doing a pretty decent job We'll have a look at whether it makes sense to devote the engineering time and effort to making the CAN implementation more generic with regard to what runs at what speed and on what bus, but don't hold your breath in the meantime. A bridge would be the most effective and quickest solution to the problem at hand.

Regarding the Teves IDs and conversion factors, I'de need to check whether we already have that or not, but if we do not and you want to supply them then it would reduce the time required for the implementation and thereby also make it more cost effective (indeed if there is sufficient demand for it and we have the info it would probably be done FoC since it has a greater market potential).

Custom CAN on an S* runs at 1Mbps and you can configure the 20 ARBIDs that you want, the transmit frequency of each ARBID and the contents of each frame. SCal will tell you the conversion factor into engineering units but right now you can't change the conversion factors on the transmit side.

Hope this helps,

Pat.

[Brendan]

Thanks Pat - that covers my questions, for the time being anyways.

Time for me to get all my vehicle hardware taken care of and start putting together a wiring diagram so I know exactly what I'll need.

[Mark_r33]

Reviving this due to interest in the E46 ABS as a standalone retrofit unit.

Did you get anywhere with this Brendan?

I'm trying to figure out what I can connect to what and how.

I'd like to be able to get at least the wheel speeds from the ABS unit, but would also still like to be able to run an AIM MXS Strada dash. Non of this would be in the BMW the ABS came from, and I'm hoping my entry level S6GP can handle it.

The Strada only has a config for the Stack stream with Syvecs, but does have a more in depth CAN config for the LR F88. Not sure on any compatibility there?

Currently I'm hoping that the Life stream can be emulated by the Syvecs custom datastream, so I can talk to the Dash but include wheel speed stuff on the bus. Then I think I will need some sort of CAN bridge to bring the ABS onto the bus so it can supply the wheel speed data?

Any help or pointers to info would be greatly received!

[stevieturbo]

A bump too...

Did they ever get the data from the MK60 ABS unit via CAN ? I could consider this ABS Swap myself if this also allowed me wheel speeds. It'd kill two birds kinda deal