NMEA 2000 Shield

Did you mean NMEA2000_CAN.h?

You should not touch any library code at all. If test example, you can take copy of it and modify that. If you need to change definition, you do it in your code before including NMEA2000_CAN.h - not modifying itself. Like this:

#define N2k_SPI_CS_PIN 10
#define N2k_CAN_INT_PIN 2
#include 

Have you modified shield? As default shield has CS on D9! Also take care that you have exactly two termination resistor on the whole N2k bus.

Hi,

I started again from scratch.

I changed in the source code "DataDisplay2":

[ Code]#define N2k_CAN_INT_PIN 21 [ /Code]

with that the:

[ Code]#define N2k_CAN_INT_PIN 2[ /Code]

and added the line:

[ /Code]#define N2k_SPI_CS_PIN 10[ /Code]

I always have the message: "CAN device ready Running ... "

I tested with a multimeter where are "cs" and "int". I am sure that: cs = 10 int = 2

I don't think see any resistance on CANH and CANL pin, I transmitted you the electrical diagram.

https://drive.google.com/open?id=1pSLUZES1smCzmFGpnB2YTR5_A15GZBnr

Now what i need to do ?

Thank you a lot.

I read the posts bit back...

When you see message "CAN device ready Running ... ", it means that Mega communicates with MCP2515 and CS must be right. You can easily test by changing CS definition to e.g. 9 and you should see "CAN device failed..."

The problem is so after MCP2515. It can be on int pin definition or chrystal definition. Example should work without interrupt, when you do not have too much traffic. So you can comment int pin definition until you get some data out.

Since you have seeed studio version it uses default 16MHz chrystal. Some other manufacturers shields uses 8 MHz chrystal and requires definition for that.

On the bus side there are two possible problems. Mixing CANH/CANL and missing termination resistors. With standard colours CANH is white and CANL is blue wire. And on bus it is best to have exactly 2 termination resistors. This means that if you measure with ohm meter between CANH/CANL, you should see 60 ohm resistance. If not, you have to add resistors to both end of the longest bus. In test table with short cable (<2 m) I have time to time only one resistor and it still works. So if you are doing table test with DST800 and Mega, close P1 on shield.

I just tested with my old Mega test board and DST800 with example DataDisplay2. The shield is my hand made, but similar as Seeeds shield except pins. - Works fine with or without interrupt. When powered, starts showing In Main Handler: 128259 Boat speed: SOW:0.00, SOG:not available, Paddle wheel ... - Works with 1 m bus with one termination resistor - Does not work without any termination resistors.

Hi,

1- When I test the program "DataDisplay2" with the code: N2k_SPI_CS_PIN 9 (he says "CAN device failed to open") When I test the program "DataDisplay2" with the code: N2k_SPI_CS_PIN 10 (he says "CAN device ready, Running ...")

So I'm sure CS is on the pin 10.

2- Quartz is a 16Mhz I'm sure.

3- I commented "N2k_CAN_INT_PIN 2" (because on my card it's the 2) because I only have one sensor on my bus (the DST800)

4- CAN_H is the white CAN_L is blue It was good for me.

5- I measured the resistance between the blue and white wires and I got 50k ohms. you can see it on the picture opposite: https://drive.google.com/open?id=1hNGhsF8VQYxYKMLATA7q3OEkh3LL2sGh

I measured the resistance on the arduino card between CAN_L and CAN_H and I get 1k ohm. you can see it on the picture opposite: https://drive.google.com/open?id=1q5l79676sQFGlV3WE8GV92MOC8IlHvIC and https://drive.google.com/open?id=1PJ5BifSC8vgfT_7LKCWT4pXdaw4lD7Gd

Question: 1-The ground of my external power supply have to be connected to the ground of my arduino board?

2- I have to connect the termination resistances. The same like in a picture: https://drive.google.com/open?id=1zlgggP77Eftuzmamiz6bxq9Y5NbVNMf

What are the values โ€‹โ€‹of the resistances?

I forgot to mension resistance, since it too obvious for me and basics of building NMEA 2000 system.

On NMEA 2000 bus you need to have one 120 ohm resistor on both longest end. This means that if you measure resistance between CANH and CANL, you should see 60 ohm resistance. NOTE! It is ohm not kilo ohm! Any drop cable on the bus should not exceed 6 m. The total length depends of used cable. For commonly used cable the maximum length is 100 m.

The 120 ohm termination resistors are just standard resistors. You do not need to buy any expensive brand resistors. Also you have one on shield, if you close P1.

There is good picture e.g. on https://en.wikipedia.org/wiki/File:NMEA2000_Modified_motor_yacht.jpg

I measured the resistance between the blue and white wires and I got 50k ohms. you can see it on my picture: Resistor_dst800

I measured the resistance on the arduino card between CAN_L and CAN_H and I get 1k ohm. you can see it on this picture: resistor_between_CANH_CANL and Resistor_between_CANH_CANL_2

https://drive.google.com/open?id=1PJ5BifSC8vgfT_7LKCWT4pXdaw4lD7Gd Question: 1-The ground of my external power supply have to be connected to the ground of my arduino board?

2- I have to connect the termination resistances. The same like in a picture: This is what i need to do ?

  1. yes

  2. You need to connect two 120 ohm termination resistors between CANH and CANL. Not between CANH and GND or CANL and GND.

Hi all. In this thread back in 2017 I found some decision about controlling a Raymarine autopilot over NMEA2000. There was some ideas but not tested yet - etc. Is there somebody there have made an Arduino board to remote control a autopilot over NMEA2000 ?

Hi all,

Is it possible to send Roll of the boat without sending Heading? If not and there are two devices sending Heading how does one select which Heading to use/read in third one?

Heading is on PGN 127250 and roll PGN 127257. So simply do not send heading message.

It is also possible to leave data out from message, which has multiple fields by defining it as NA. Then if there is e.g. two different devices sending engine data with PGN 127489, one can do

SetN2kEngineDynamicParam(N2kMsg,0,EngineOilPress,EngineOilTemp,N2kDoubleNA,N2kDoubleNA,N2kDoubleNA,N2kDoubleNA);

and other

SetN2kEngineDynamicParam(N2kMsg,0,N2kDoubleNA,N2kDoubleNA,EngineCoolantTemp,AltenatorVoltage,N2kDoubleNA,N2kDoubleNA);

The receiver should combine data right.

If there are really two devices sending heading, there should be way on receiver side to select, which one to use. Some MDF:s has that some does not. if you are making your own device, you should use my N2kDeviceList module and lock the device you want to follow to device "NAME" not source address, since that may change due to address claiming.

PGN 127257 contains Yaw which is commented as Heading in radians. I will test today if the display will display it too as heading. Should be able to select correct data to be shown based on device name if PGN 127257 heading is also shown as heading . Also should be able to select heading for the third device by sending and reading PGN 127250.

thank you

You can also do:

SetN2kAttitude(N2kMsg,0xff,N2kDoubleNA,N2kDoubleNA,Roll);

Hi to all

Sorry that my question not linked with this great NMEA library, but it is experienced NMEA-community so I will try...

I make own stm32 project.

Does anybody has experience with correct PGN 127497 generation? to be displayed on MFDs.

We produce 2 PGNs: 127497 and 127489, they both longer than 2 bytes and must be sent in separate packets. We do it in the same procedure for both, but results are different:

Checked by Actisence reader software: https://imgur.com/3FsuMOQ

PGN 127489 is displayed correctly, assembled from 2 packets PGN 127497 is displayed as 2 separate messages, first one contains correct information (but named as 8-byte message, though it has 9 bytes) but second one totally not correct, belong to another engine instance and ruin the information on the display when we connect real device under this instance.

https://imgur.com/Ytx5Ih1

May be somebody has an example of raw CAN bus log with successful PGN 127497 sending and receiving.

many thanks!

The PGN127497 is fast packet and not listed on library fp messages, so it can not receive it right. I can add this in coming days.

If you need it immediately, other option is that you add it to known list with tNMEA2000 class function ExtendFastPacketMessages and create handlers by yourself. You can then switch handlers, when I have added it. Please do not add handlers to library modules, so your own handlers will not be deleted on library update.

Thank you for reply, Timo

We didn't use your great library for Arduino, we made it from scratch on our STM-controller (already had J1939 implemented before).

PGN 127489 is fast packet message too and decoded right by Actisense. So it is confusing for us why same algorythm for 127489 and 127497 provides different results when connected to real devices (Actisense, MFD).

Will try your library too (have arduino Duo) and compare, thanks!

Hi Timo,

I could not find the multimedia class 125 and functions (130&140) so I guess it is not implemented. Could that be interesting as there is so less device supporting the nmea2k? Thought about building a media central controllable by the MFD.

There is no multimedia PGN functions on the library. On N2kMessages module are the most common PGNs. It is pretty simple to create new module e.g. N2kMultimedia.h/.cpp and write functions as in N2kMessages.

Hello all, For starters, I would like to thank Timo for the wonderful work on the library. I'm impressed.

I'm doing tests on the Arduino Mega and MCP2515. At the moment everything works very well. On this weekend I will be testing with the ST-NG network with Raymarine devices: i70, i70s and Ray260 radio with AIS receiver.

My question is about the NMEA2000ToNMEA0183 example. Have you already tried to translate AIS messages from NMEA2000 to NMEA0183? I would like to display AIS data on OpenCPN.

Best regards,

AIS conversion has been on my list for long time, but unfortunately since I do not need it just now, it is not on the top of my list. And I have pretty much work to do.

Do you have any examples of how to use PGN 127489 with Arduino DUE? I read all the documentation, maybe I did not understand, but I only get the messages on the serial.

22:44:58.492 -> Start add 0 22:44:58.492 -> Initialize buffers 22:44:58.492 -> CAN device ready 22:44:58.679 -> Start address claim for device 0 22:45:07.684 -> PGN 127489, frame:3/4 send failed 22:45:08.688 -> PGN 127489, frame:0/4 send failed 22:45:09.696 -> PGN 127489, frame:0/4 send failed 22:45:10.704 -> PGN 127489, frame:0/4 send failed

Regards

timolappalainen: Heading is on PGN 127250 and roll PGN 127257. So simply do not send heading message.

It is also possible to leave data out from message, which has multiple fields by defining it as NA. Then if there is e.g. two different devices sending engine data with PGN 127489, one can do

SetN2kEngineDynamicParam(N2kMsg,0,EngineOilPress,EngineOilTemp,N2kDoubleNA,N2kDoubleNA,N2kDoubleNA,N2kDoubleNA);

and other

SetN2kEngineDynamicParam(N2kMsg,0,N2kDoubleNA,N2kDoubleNA,EngineCoolantTemp,AltenatorVoltage,N2kDoubleNA,N2kDoubleNA);

The receiver should combine data right.

If there are really two devices sending heading, there should be way on receiver side to select, which one to use. Some MDF:s has that some does not. if you are making your own device, you should use my N2kDeviceList module and lock the device you want to follow to device "NAME" not source address, since that may change due to address claiming.