Connecting the Can CON module to a CAN Bus problems

Topics about the Hardware of Revolution Pi
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gcoban
Posts: 4
Joined: 14 Apr 2020, 13:56
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Connecting the Can CON module to a CAN Bus problems

Post by gcoban »

I am looking to buy the RevPI connect and the Can CON module but I are not sure if this the right hardware. I did not understand how to connect this to the CAN bus
https://revolution.kunbus.com/tutorials ... chliessen/ on this website you can see that it has 4 signals, I understood the CAN_H and CAN_L, this is what a node needs to connect to a CAN Bus.
I also understand what the 2x 60 ohm are for, for reducing noise and the 2.5V is the voltage that the CAN_H and CAN_L work with.

We could not find this in the forums nor in the FAQ, so I have a few questions for which the technical support referred me to this forum:

1. How do we connect this module to the CAN Bus? Some sub questions which are more helpful:
a. How do we connect the resistor and the 2.5V? Pins 1 and 4. It does not make sense to have a 2.5 V power source here since there is no ground going back to this eventual power source and the RevPI works with 5v right?
b. How to connect the resistors to pin 1 and 4 or is this internally connected? Which is the +, which is the - ?
c. Is there example wiring for the CON CAN module, how to connect the X2 to the CAN Bus? I could not find anything
2. How does the module work with shielding? Our system has uses the SAE J1939 standard and this uses CAN_H, CAN_L and CAN_Shield. How does this module handle the shielding, e.g how does the shield terminate in the connector? We are worried that we cannot terminate the shield correctly and that this would not create a complete shielding effect

Thanks in advance!
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dirk
KUNBUS
Posts: 1942
Joined: 15 Dec 2016, 13:19
Answers: 4

Re: Connecting the Can CON module to a CAN Bus problems

Post by dirk »

Hi gcoban, puh this seams to be many questions that target the same thing. So you alredy pointed out the rigth page "How to Connect RevPi Con CAN to the CAN Bus"
pins documentation
pins documentation
2020-04-14 17_14_42-Window.jpg (9.65 KiB) Viewed 4771 times
So here is a practical example:
pinning real
pinning real
Pinning1.jpg (9.73 KiB) Viewed 4771 times
D-SUB9 connector
D-SUB9 connector
Pinning2.jpg (18.89 KiB) Viewed 4771 times
But currently I cannot answer your question "How does the module work with shielding?"
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dirk
KUNBUS
Posts: 1942
Joined: 15 Dec 2016, 13:19
Answers: 4

Re: Connecting the Can CON module to a CAN Bus problems

Post by dirk »

Hi, regarding your question "How does the module work with shielding?":
The RevPi Con CAN itself has no shield connection. A shielded cable should be used for CAN, especially for longer lengths. The screen can be contacted in different ways:
- When the line enters the control cabinet:
https://www.lappkabel.de/produkte/onlin ... ]=53112531

-- Good RF properties
-- Protection against transient overvoltages.

- with a metal clamp on the grounded mounting plate or top hat rail:
https://www.icotek.com/ch/produktkatalo ... ng/sfzskl/
-- Good RF properties
-- Protection against transient overvoltages.

- Twist the screen into a pigtail and then connect it to the earth terminal
-- Very poor RF properties
-- Only protection against transient overvoltages.
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