joewiki
Newbie level 1
I'm working on a car project where I need to connect multiple devices ( more than 3) to the same CAN bus. One of these devices is supposed to go in the engine compartment and the rest of them inside the car (possibly as far as the trunk). Each device is an electronic board, like the CAN-BUS-Shield-V1.2 for Arduino, with screw terminals to connect to the CAN-H and CAN-L signal wires of the bus.
My questions...
1) What type of connectors, if any, should I use? Specially to tap a device (node) into the bus? . I read that DB-9 is the industry standard connector for CAN bus, but can't a female-female-male Tee-connector . I also read that M12 and 5 pin mini C connectors are used in some CAN bus applications.
Links to online parts are greatly appreciated.
2) Assuming no connectors are necessary, whats the best way to make a 3 way connection for each wire in a twisted pair?
3) Should I look for a specific cable . I'm specifically wondering about,
(1) Wire gauge (considering that the wires have to be run several feet go from trunk to engine compartment)
(2) Shielded cable vs unshielded twisted pair of wires.
(3)Characteristic impedance.
A link to a suitable cable/wires sold online is greatly appreciated.
4) Assuming a shielded cable is used, is it ok if the shield conductor doesn't carry the reference ground?
5) All of the boards already have the CAN signals connected with 120 ohms resistors, but those resistors can be switched out. I understand that two and only two terminations should exist between the two CAN signals . Should I consider switching out the resistors in the boards, and instead use external 120 ohm terminators?
6) Lastly. I never done any hands-on work. Anybody has an idea how to run wires through the firewall?. The car we are working on is a Kia Soul.
Please note that this CAN bus is separate from any CAN bus already in the vehicle and has nothing to do with the OBD connector that is found in the vehicle's cabin.
Thanks so much
My questions...
1) What type of connectors, if any, should I use? Specially to tap a device (node) into the bus? . I read that DB-9 is the industry standard connector for CAN bus, but can't a female-female-male Tee-connector . I also read that M12 and 5 pin mini C connectors are used in some CAN bus applications.
Links to online parts are greatly appreciated.
2) Assuming no connectors are necessary, whats the best way to make a 3 way connection for each wire in a twisted pair?
3) Should I look for a specific cable . I'm specifically wondering about,
(1) Wire gauge (considering that the wires have to be run several feet go from trunk to engine compartment)
(2) Shielded cable vs unshielded twisted pair of wires.
(3)Characteristic impedance.
A link to a suitable cable/wires sold online is greatly appreciated.
4) Assuming a shielded cable is used, is it ok if the shield conductor doesn't carry the reference ground?
5) All of the boards already have the CAN signals connected with 120 ohms resistors, but those resistors can be switched out. I understand that two and only two terminations should exist between the two CAN signals . Should I consider switching out the resistors in the boards, and instead use external 120 ohm terminators?
6) Lastly. I never done any hands-on work. Anybody has an idea how to run wires through the firewall?. The car we are working on is a Kia Soul.
Please note that this CAN bus is separate from any CAN bus already in the vehicle and has nothing to do with the OBD connector that is found in the vehicle's cabin.
Thanks so much
