OpenMarine
CAN BUS - Printable Version

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CAN BUS - Spidgrou - 2021-05-03

Hi Guys,
I'm using with success the RS485-CAN-HAT (MCP2515), I can read without any problem the NK2 data from my boat.

Now, I would like to read also the data coming from my Battery charger, it is a Quick SBC 1100 NRG 80A.
It has the Can-Bus Exit wih the two wires L and H
I tried to connect to the same network in parallel with the N2K but I can't see anything.

Is it possible to stay on the same network or they have to work separately?

Any help is appreciated.
Thanks.
Max
s/y Y2K

IRS485-RSRS485-CAN-HAT (MCP2515)485-CAN-HAT (MCP2515)CAN-HAT (MCP2515)



RE: CAN BUS - holgerw - 2021-05-03

Most RS485-CAN-HATs have an 120 ohm Restistor between H And L soldered. Remove this with an sharp Knife or your fingernail... you can check this an Multimeter. But without powering the HAT! It should read something in the K-Ohms after removal.

On an correct Bus, like your Bus on the Boat now (also powerless, not active) the Multimeter should read 60 Ohm - with Terminatorresistors at both End from the Busline.

Good Luck
Holger


RE: CAN BUS - Techstyle - 2021-05-03

your battery charger doesn't say its NMEA2K it says it has a CAN Bus. you would have to look at what the protocol is and then work out how you decode it into some useful messages.

I think you may need separate networks if it is not the same protocol, but i am not sure


RE: CAN BUS - Spidgrou - 2021-05-04

(2021-05-03, 04:28 PM)Techstyle Wrote: your battery charger doesn't  say its NMEA2K it says it has a CAN Bus.  you would have to look at what the protocol is and then work out how you decode it into some useful messages.

I think you may need separate networks if it is not the same protocol, but i am not sure

Thanks,
I will contact the manufacturer and ask them more for this connection.

(2021-05-03, 07:39 AM)holgerw Wrote: Most RS485-CAN-HATs have an 120 ohm Restistor between H And L soldered. Remove this with an sharp Knife or your fingernail... you can check this an Multimeter. But without powering the HAT! It should read something in the K-Ohms after removal.

On an correct Bus, like your Bus on the Boat now (also powerless, not active) the Multimeter should read 60 Ohm - with Terminatorresistors at both End from the Busline.

Good Luck
Holger

Thanks for that. 
I will check soon


RE: CAN BUS - SCarns - 2021-05-04

(2021-05-03, 04:28 PM)Techstyle Wrote: your battery charger doesn't  say its NMEA2K it says it has a CAN Bus.  you would have to look at what the protocol is and then work out how you decode it into some useful messages.

I think you may need separate networks if it is not the same protocol, but i am not sure

I second Techstyle's analysis. From my own messing around with my solar charger, I can clearly summarize that CAN and NMEA2000 are very different and will require separate connections. Otherwise, you could simply adapt the charger to the N2K network. But, it's not that simple. 

N2K has clearly defined PGN sentences. With my limited experience with CAN, I can tell you one needs to know where the data is in the bus and how many bytes you need to read to get accurate data. There might be some hexadecimal to binary conversion needed. On one hand, CAN seems quite rudimentary and that is what makes it difficult.