CANBus Wiring methods

Hello all!

I want inquire about CAN Bus wiring. This is regarding a system I'm putting together for a friend.

It will incorporate a Motec M130, a C127, PDM15, Keypad, and LTCD.

My first question is about device order and why it's important.

Second question is knowing when to daisy chain or when to make a trunk and splice off to stubs connecting to the devices.

I have attached a PDF of my configuration as a draft for my design and would like some critique on how I set it up.

(Page 1 is device order, top to bottom. Page 2 is daisy chain method, splicing at each device termination. Page 3 consists of the trunk from first device to the last, with splices going out to about 40cm max. per device.

Thanks in advance!

Hello,

I would recommend following the CAN wiring guidelines which are included in most of the MoTeC documentation.

ChariotOfGold,

Your order looks acceptable.

The difference between what's on Page 2 and Page 3 comes down to how you execute the branching. Page 3 is the traditional way and how you'll generally be directed. What it physically looks like in the vehicle will vary with the lengths you actually need.

Technically what's on page 2 would likely work as well if executed properly, but page 3 utilizing a trunk is what I stick to because my experience has been that sometimes you can deviate from suggested CAN wiring and get away with it, and sometimes you cant. To have success every time, following the rules is your best bet. Scott's Motec suggestions are based on the standard and will generally keep you out of trouble. I've had some legs far longer than that spec without issue, but I don't count on it.