Exemple Modbus master doesn't working

[sl446]

Hello sir,

I am experiencing an issue with the Canopus version 1 board. The Modbus Master example code available on GitHub is not working, and my own code that uses the frames is also not working.

this is your exemple code :

#include "Canopus_Modbus.h"
ModbusMaster node;
#include <Rak3172_Canopus.h>
#define V_RS485 PB12

#define V1
uint8_t result;
void setup()
{
  pinMode(V_RS485, PWR_ON);
  pinMode(PB2, OUTPUT);
  Serial.begin(115200);
  Serial.print("\r\n*****************RAK3172_CANOPUS*******************");
  Serial_Canopus.begin(9600, SERIAL_8N1);
}
void loop()
{
  //***************READ node 1**************************
  node.begin(1, Serial_Canopus); //slave ID node
  Serial.printf("");
  Serial.printf("\r\n\n\nExample read modbus RTU for RAK3172_Canopus board");

  result = node.readHoldingRegisters(0, 1);//Read 40000 to 40009
  delay(10);
  if (result == node.ku8MBSuccess) //Read success
  {
    for (uint8_t i = 0; i < 10; i ++ )
    {
      Serial.printf("\r\nValue 4000%d: %d", i, node.getResponseBuffer(i));
    }
  }
  else Serial.print("Read Fail node 1"); //read fail
  digitalWrite(PB2, !digitalRead(PB2)); //blink led
  delay(500);
}

And this is my code, using frames (when i run this code i see tx led blinking but with a dim light):

#include <Rak3172_Canopus.h>  // Include the Rak3172_Canopus library header file.
#include "Canopus_Modbus.h"
#include "Rak3172_Canopus.h"
#define V1
#define RS485_VCC PB12

byte Temp[] = {0x01, 0x03, 0x00, 0x00, 0x00, 0x01, 0x84, 0x0a};
byte responseBuffer[50]; // Taille du tampon de réponse
float Value, Val1;

void setup() {
  Serial.begin(115200);
  Serial_Canopus.begin(9600, SERIAL_8N1);
  pinMode(RS485_VCC, OUTPUT);
  digitalWrite(RS485_VCC, PWR_ON);  //On power Vrs485
  //pinMode(V_SS5, PWR_ON);
}

float temp(){
//  node.begin(1, Serial_Canopus); //slave ID node
  RS485_Tranmit;
  Serial_Canopus.write(Temp, sizeof(Temp));// Envoyer la requête au capteur

  // Lire la réponse
  RS485_Receive;
  delay(200);
  int responseLength = Serial_Canopus.available();
  if (responseLength > 0) {
    for (int i = 0; i < responseLength; i++) {
      responseBuffer[i] = Serial_Canopus.read();
    }
      Value = (responseBuffer[3] << 8) | responseBuffer[4];
      Value = Value/100;
      Serial.print("temperature : ");
      Serial.print(Value);
      Serial.println(" °C");
  } else {
    Serial.println("Aucune réponse reçue.");
  }

  return Value;
}

void loop() {

  Serial.println("________________________");
  temp();
  delay(1000);

}

notice 1 : i use a Seeed studio EC sensor (RS485, 12V) i use a externel alimentation with this sensor and the seem gnd for all the system. notice 2 : i have also an conveter usb to RS485 for test.

[NamNamIoT]

Fixed. The reason is PB12 in V1 can not active power for rs485 block. Change to use power of I2C port (PB5). This issue in hardware was fix on version 2, currently we have version 3.

[sl446]

Thank you very much. The problem has been resolved.