I am using a NodeMCU ESP8266 WiFi board for collecting N - P - K sensor data. I am using RS485 as interface.
This is the code:
#include <SoftwareSerial.h>
#define RE D6
#define DE D7
#define RO D0
#define DI D1
const byte nitro[] = {0x01,0x03, 0x00, 0x1e, 0x00, 0x01, 0xe4, 0x0c};
const byte phos[] = {0x01,0x03, 0x00, 0x1f, 0x00, 0x01, 0xb5, 0xcc};
const byte pota[] = {0x01,0x03, 0x00, 0x20, 0x00, 0x01, 0x85, 0xc0};
byte values[11];
SoftwareSerial mod(RO , DI); //R0 and DI
void setup(){
pinMode(RE, OUTPUT);
pinMode(DE, OUTPUT);
// put RS-485 into receive mode
digitalWrite(DE, LOW);
digitalWrite(RE, LOW);
Serial.begin(9600);
mod.begin(9600);
Serial.println("Code started");
byte nitrogen_value = nitrogen(); //N value
delay(1000);
byte phosphorous_value = phosphorous(); //P value
delay(1000);
byte pottasium_value = potassium(); // K value
delay(1000);
Serial.println("Values are:");
Serial.println(nitrogen_value);
Serial.println(phosphorous_value);
Serial.println(pottasium_value);
}
void loop(){
}
byte nitrogen(){
digitalWrite(DE,HIGH);
digitalWrite(RE,HIGH);
delay(1000);
if(mod.write(nitro,sizeof(nitro))==8){
digitalWrite(DE,LOW);
digitalWrite(RE,LOW);
Serial.print("Executing Nitrogen");
for(byte i=0;i<7;i++){
values[i] = mod.read();
Serial.print(values[i],HEX);
}
Serial.println();
}
return values[4];
}
byte phosphorous(){
digitalWrite(DE,HIGH);
digitalWrite(RE,HIGH);
delay(1000);
if(mod.write(phos,sizeof(phos))==8){
digitalWrite(DE,LOW);
digitalWrite(RE,LOW);
for(byte i=0;i<7;i++){
values[i] = mod.read();
Serial.print("Executing Phosporous");
Serial.print(values[i],HEX);
}
Serial.println();
}
return values[4];
}
byte potassium(){
digitalWrite(DE,HIGH);
digitalWrite(RE,HIGH);
delay(1000);
if(mod.write(pota,sizeof(pota))==8){
Serial.print("Executing pottasium");
digitalWrite(DE,LOW);
digitalWrite(RE,LOW);
for(byte i=0;i<7;i++){
values[i] = mod.read();
Serial.print(values[i],HEX);
}
Serial.println();
}
return values[4];
}
During execution I always get 255 as output
Please help me to find the mistake and error.
