Hi,
Trying to use rs485 for sending and receiving data from solar inverter. The message format is for example
8 Bytes key provided by VENDOR
0xXX 0xXX 0xXX 0xXX 0xXX 0xXX 0xXX 0xXX
Example Send : 01 10 90 00 00 04 08 01 00 00 00 00 00 00 00 B6 E7
Receive : 01 10 90 00 04 1C EE
Port settings:
- Baud rate : 9600
- Data bits per Byte : 8
- Parity : None
- Stop bits : 1
MSG format
The Modbus version used is RTU (mode master/slave).
The Modbus protocols define a format for the master query and the slave response, the DEVICE is defined as the slave for the communication.You must wait for the DEVICE to send a response back or reach the 10s timeout before sending a new command, otherwise you may receive all the response at once.
I need help on my current approach which is not working. Any pointers are much appreciated !
#include <SoftwareSerial.h>
// assemble message
byte msg [] = {
0x01,
0x10,
0x90,
0x00,
0x00,
0x04,
0x08,
0x01,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0xB6,
0xE7
};
#define TX_ENABLE_PIN 3 // DE-RE from HW-97 to pin 3 on nano
SoftwareSerial rs485(1, 0); // Arduino NANO
#define RS485Transmit HIGH
#define RS485Receive LOW
void setup(){
pinMode(TX_ENABLE_PIN, OUTPUT); // driver output enable
rs485.begin (9600);
Serial.begin(9600);
Serial.println("Setup DONE !");
}
void loop(){
// Send data
Serial.println();
digitalWrite (TX_ENABLE_PIN, HIGH); // enable transmit
Serial.print(a);
rs485.write(a);
for (int i = 0; i < sizeof(msg); i++) {
Serial.print(msg[i], HEX);
rs485.write(msg[i]);
Serial.print(", ");
}
rs485.flush();
Serial.println();
digitalWrite(TX_ENABLE_PIN, LOW); // disable transmit
delay(1000);
// Try to read back
Serial.println();
Serial.write(rs485.read());
delay(1000); // Wait a while
}
