Read CAN message from a machine

[andreoracio]

Hello guys,

I'm trying to read a CAN message with Arduino, this message is sent by a machine.

When I prepare a message to send from an Arduino and prepare a second Arduino to read that message, ok I have no doubts.

But how do I read a message sent by a machine?

I already know the message I read using the "can analyzer", the ID is: 18FFEE8D, the DLC is 8.

How do I configure Arduino to read this message when it is sent by the machine?

can you help me?

[kolaha]

you send ID and receive 8 bytes

[andreoracio]

like this?

i need to read the message the machine sends and not send a message to the machine.

[kolaha]

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[TomGeorge]

Hi,
What is the machine?
What CanBus module are you using?
What speed is the CanBus?

Thanks.. Tom...

[andreoracio]

Hello,

I don't know exactly which machine it is, but I can guarantee that it sends the message in the attached image:

I'm using Arduino Nano + MCP2515

If I were to read a message sent by another arduino, I would use the code below:

#include <SPI.h>
#include <mcp2515.h>

struct can_frame canMsg;
MCP2515 mcp2515(10);


void setup() {
  Serial.begin(115200);
  
  mcp2515.reset();
  mcp2515.setBitrate(CAN_125KBPS);
  mcp2515.setNormalMode();
  
  Serial.println("------- CAN Read ----------");
  Serial.println("ID  DLC   DATA");
}

void loop() {
  if (mcp2515.readMessage(&canMsg) == MCP2515::ERROR_OK) {
    Serial.print(canMsg.can_id, HEX); // print ID
    Serial.print(" "); 
    Serial.print(canMsg.can_dlc, HEX); // print DLC
    Serial.print(" ");
    
    for (int i = 0; i<canMsg.can_dlc; i++)  {  // print the data
      Serial.print(canMsg.data[i],HEX);
      Serial.print(" ");
    }

    Serial.println();      
  }
}

[andreoracio]

The speed is 250 kbps

[TomGeorge]

Hi,

@andreoracio

I don't know exactly which machine it is,

What do you mean by that?

What do you expect your project to do?

Thanks.. Tom...

[kolaha]

@andreoracio

The speed is 250 kbps

mcp2515.setBitrate(CAN_250KBPS); 

?

[andreoracio]

@TomGeorge

@andreoracio

I don't know exactly which machine it is,

What do you mean by that?

What do you expect your project to do?

I think it doesn't matter which machine it is, what matters to me is that it sends this CAN message and I need to read it...

But that's ok, the machine is a "Caterpillar cat 320" and I need to read this CAN message to convert it to RS232...

So my problem is: How do I read this message?

[horace]

if you do a web search for arduino canbus you will get get plenty of links

[andreoracio]

Hi Horace, you're right....

And the code that I posted here is one of those many examples and it works very well, but on a bus between Arduinos, because I prepare the "Arduino 2" to receive the message sent by the "Arduino 1", that is, I configure the 2 devices. ...

In my case, I need to read the message that comes from the machine (Caterpila CAT320), if it were as simple as the examples available, I wouldn't need a CANanalyzer to read the messages from the machine, I would simply plug the Arduino and that's it.

But I already managed to move forward, I discovered the messages sent by (as posted above), now I need to know what I need to change in the code below so that the Arduino receives this message....

#include <SPI.h>
#include <mcp2515.h>

struct can_frame canMsg;
MCP2515 mcp2515(10);


void setup() {
  Serial.begin(115200);
  
  mcp2515.reset();
  mcp2515.setBitrate(CAN_250KBPS);
  mcp2515.setNormalMode();
  
  Serial.println("------- CAN Read ----------");
  Serial.println("ID  DLC   DATA");
}

void loop() {
  if (mcp2515.readMessage(&canMsg) == MCP2515::ERROR_OK) {
    Serial.print(canMsg.can_id, HEX); // print ID
    Serial.print(" "); 
    Serial.print(canMsg.can_dlc, HEX); // print DLC
    Serial.print(" ");
    
    for (int i = 0; i<canMsg.can_dlc; i++)  {  // print the data
      Serial.print(canMsg.data[i],HEX);
      Serial.print(" ");
    }

    Serial.println();      
  }
}

[horace]

if the canbus is connected correctly and the can speed is correct you should see messages on the serial monitor consisting of ID, message length then the data (up to 8 bytes)
do you see anything - if nothing try changing the CAN speed ?
when debugging CAN I find a USB CAN dongle which plugs into a PC useful for chacking network operation and debugging
can you give us a schematic of your wiring?

[TomGeorge]

Hi,

@andreoracio

the machine is a "Caterpillar cat 320" and I need to read this CAN message to convert it to RS232...

Have you Googled;

caterpillar canbus protocol

Do you know the PIDs that you want to monitor?

Tom....

[TomGeorge]

Hi,
If the PIDs are ODB2 then this may help.
Google;

arduino reading canbus PIDs

OBD-II CAN Library Help Reading PIDs

Hello, I just got the OBD-II CAN-BUS Development Kit from Seeed Studio. I connected the CAN module to the OBD cable (CAN High and CAN Low) and to an Arduino Uno (Pins D2 and D3 for RX and TX, respectively) and plugged it into my car running the "recv" example program using this library: GitHub - Longan-Labs/Serial_CAN_Arduino I was able to see a flow of input in the serial monitor displaying PIDs and their data. I'll post the original example code just so you can see it here. // RECV EXAMPLE …

Tom....

[andreoracio]

Hi guys, I managed to solve my problem.

To read messages on the CAN network of a machine, just use the command below:

 if (mcp2515.checkReceive())
    {
        mcp2515.readMessage(&canMsg1);

And if the ID is already known, just filter as below:

 if (canMsg1.can_id == 0x80FFEA28)

And we can still filter by the data as below:

if (canMsg1.data[i] == 0x01)

In the end, this is my complete code:

#include <Arduino.h>
#include <SPI.h>
#include <mcp2515.h>
#include <SoftwareSerial.h>

SoftwareSerial serial_tel (7, 8); //Define RX/TX por Software

struct can_frame canMsg1;

MCP2515 mcp2515(10);

void setup() 
{

  Serial.begin(9600);
  serial_tel.begin(9600);

  mcp2515.reset();
  mcp2515.setBitrate(CAN_500KBPS);
  mcp2515.setNormalMode();

  Serial.println("------- SERIAL DISPONIVEL --------");
}

void loop() 
{
    if (mcp2515.checkReceive())
    {
        mcp2515.readMessage(&canMsg1);

        if (canMsg1.can_id == 0x80FFEA28)
          {
            int i = 0;

            if (canMsg1.data[i] == 0x01)
            {
              Serial.println("AT+GTDAT=9875,2,,PEDESTRE PERIGO,0,,,,FFFF$");              
              serial_tel.println("AT+GTDAT=9875,2,,PEDESTRE PERIGO ,0,,,,FFFF$");
              delay(10000);
            }

            if (canMsg1.data[i] == 0x02)
            {
              Serial.println("AT+GTDAT=9875,2,,PEDESTRE CUIDADO ,0,,,,FFFF$");
              serial_tel.println("AT+GTDAT=9875,2,,PEDESTRE CUIDADO ,0,,,,FFFF$");
              delay(10000);
            }      
    }
  }
}

This is my Caterpilla....

[TomGeorge]

Caterpillar 320??????????????????????