How to interface CAN Bus with Smart Actuator

Mbed OS
,
1

Hi I’m new to Mbed
Is there anyone have ever interface a smart actuator(RMD-X8) with CAN bus.
Right now I know protocol of the actuator but I don’t know how to start coding to drive this actuator and there is no tutorial too.
I’m using NUCLEO F446RE
Thank you.

2

Hi there,

if you are newbie, it is good to start with Mbed’s documentation - Mbed OS quick start.
I saw a video about that part and it looks like a nice toy but a little expensive for me.

For the start you need next to your board:

I tried to write only a simple program, which ask about a current PID setting of servo, it wait for response and then it end. Keep it mind it is only experimental code according to documents above, I not have this hardware.

#include "mbed.h"

#define DEVICE_CAN_ID 141 //identifier: 0x140+ID(1-32)

DigitalOut led1(LED1);
CAN can(PB_8,PB_9,1000000); //I am not sure with with frequency but  in the video 1000kbps is used
char data[] = {0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; //read PID param. cmd

int main()
{
    printf("CanTest\n");
    ThisThread::sleep_for(500ms);
    if (can.write(CANMessage(DEVICE_CAN_ID, data))) { 
        CANMessage msg;
        while (1) {
            if (can.read(msg)) {
                // Printing what was read
                printf("Message received:[ ID: %9x", msg.id);
                printf(" Length: %d", msg.len);
                printf(" Command: %2x", msg.data[0]);
                //printf(" %2x", msg.data[1]); // Null
                printf("Position loop Kp %2x", msg.data[2]);
                printf("Position loop Ki %2x", msg.data[3]);
                printf("Speed loop Kp %2x", msg.data[4]);
                printf("Speed loop Ki %2x", msg.data[5]);
                printf("Torque loop Kp %2x", msg.data[6]);
                printf("Torque loop Ki %2x", msg.data[7]);
                printf("CanBus Type: %d", msg.type);           // 0 = data, 1 = remote
                printf("Format: %d ]\r\n", msg.format);        // 0 = standard, 1 = extended
                ThisThread::sleep_for(500ms);
                break;
            }
            ThisThread::sleep_for(100ms);
            led1 = !led1;
        }
    }else{
        printf("Write error\n");
    }
    printf("Rrogram end!\n");
}

BR, Jan

1 Like
3

Thank you so much.