groundFungus:
Software serial and serial event do not work together. Serial event is just for the hardware Serial (pins 0 and 1). Just use Serial3.available() in loop. See this post.. Or this post.
I have modified the code so and now the temperature value appears on the screen, and in the pH it gives -1.
#include <Adafruit_MAX31856.h>
#include <SoftwareSerial.h>
Adafruit_MAX31856 max_A = Adafruit_MAX31856(10, 11, 12, 13);
String termoparstring_A = "";
String sensorstring = "";
String inputstring = "";
#define rxPin 7
#define txPin 6
SoftwareSerial Serial3 (rxPin,txPin);
boolean input_string_complete = false;
boolean sensor_string_complete = false;
void setup() {
Serial.begin(9600);
pinMode(rxPin,INPUT);
pinMode(txPin,OUTPUT);
Serial3.begin(9600);
inputstring.reserve(30);
sensorstring.reserve(60);
max_A.begin();
max_A.setThermocoupleType(MAX31856_TCTYPE_K);
}
void loop() {
termoparstring_A =(max_A.readThermocoupleTemperature());
Serial3.listen();
while (Serial3.available() > 0) {
char sensorstring = Serial3.read();
}
sensor_string_complete = true;
sensorstring = Serial3.read();
Serial.println(termoparstring_A);
Serial.println(sensorstring);
delay(500);
sensorstring = "";
sensor_string_complete = false;
}