Forum » General Tuning Discussion » CAN Inputs/Outputs/Power Distribution

CAN Inputs/Outputs/Power Distribution

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 


Page 1
Author
47 Views

My E46 has a turbo m52 and is about ready to get rewired after paint is finished on the cage!

The modules I want to communicate via CAN are:

-AIM MXS 1.2 Dash with remote button interface CAN box

-LINK Fury

-CANEGT module

-ECUMaster PMU power distribution module

-ECUMaster 12 button CAN keypad

-I also have a Painless wiring relay box which will power a lot of things via ground trigger switches.

The first part of my question is do I want to put these all on a single CAN network, or have them split up. for example, have the dash communicate with the Link ecu on its own, then the ECU communicate with the CANEGT and PMU on another?

Is there a way to wire inputs to the dash to trigger things on the ecu like 2step and scramble boost via CAN?

Has anybody had experience broadcasting engine signals such as temperature and pressures from the PDM and having the LINK use them as inputs, and vice versa? I ask because that frees up a ton of inputs on the LINK and also lets the car continue even if a sensor fails and shorts the non-essential 5v power source coming from the PDM. This has happened to us before. A pressure sensor failure took down all of the others including MAP which killed the car. I would like to keep the essential 5v sensors powered and wired directly to LINK, like MAP and Lambda, and let the rest go to the PDM, and then transitioned from PDM to LINK

Please google drive excel to see what I want to trigger and power what, etc.

https://docs.google.com/spreadsheets/d/19sOWsE4amSYvxEnjeqqLvCBF-ciw_2l3b1YDAJpMpgA/edit?usp=sharing

Thanks! input is greatly appreciated

"The first part of my question is do I want to put these all on a single CAN network, or have them split up. for example, have the dash communicate with the Link ecu on its own, then the ECU communicate with the CANEGT and PMU on another?"

Yes, easiest to put them all on the same bus. You will be no where near the bandwidth limit. All of your devices have configurable ID's and baud rates so no conflicts there to worry about.

"Is there a way to wire inputs to the dash to trigger things on the ecu like 2step and scramble boost via CAN?"

Yes, we can do this. The link has 8 general purpose "CAN digital inputs", the dash will need a custom CAN stream set up but I can help you with that.

"Has anybody had experience broadcasting engine signals such as temperature and pressures from the PDM and having the LINK use them as inputs, and vice versa? I ask because that frees up a ton of inputs on the LINK and also lets the car continue even if a sensor fails and shorts the non-essential 5v power source coming from the PDM. This has happened to us before. A pressure sensor failure took down all of the others including MAP which killed the car. I would like to keep the essential 5v sensors powered and wired directly to LINK, like MAP and Lambda, and let the rest go to the PDM, and then transitioned from PDM to LINK"

As for receiving pressures and temperatures into the ECU via CAN there are some limitations. I will attach a pic below of the current inputs that can be "natively" received via CAN (ie they will work exactly like a hard wired input), as you can see the analog inputs category is fairly brief. Oil press, fuel press and exhaust press are there, but no temps. There are 8 general purpose "CAN AN Volt" channels down the bottom of the list but they are less useful than the native ones as they are fixed to "Volts" as units and you cant label/rename them. You can however scale them so for instance if you where stuck you could set it up so that "gearbox temp = 200°F" is displayed/logged as "CAN AN Volt 1 = 200.0V".

Going the other way is easier. For things like your cooling fan and fuel pump etc, the best way is usually to set these up as virtual auxiliaries in the ECU, then just send the virtual aux status to the PDM. This means you dont need complex logic in the PDM to do fuel pump prime and fan temp hysteresis etc and to change say the fan switching temp it is all easy to find in the usual place in the ecu software.

If you want some help with the CAN stuff I suggest you put a post on the Link forum and I will help out there. This forum is a bit painful with attaching and/or linking to files and if I have to spend some time writing a CAN config I like it to be available for others to use or view for learning.

Thank you! Ill get my ducks in a row and post there.