I am using a NodeMCU v3 + Max 31865 PT100 interface board
I am seeing some strange behaviour that I don’t understand and would appreciate some assistance if anybody has any insight?
I can get Max31865 to interface perfectly using the basic example Library code as below.
#include <Adafruit_MAX31865.h>
// Use software SPI: CS, DI, DO, CLK
Adafruit_MAX31865 thermo = Adafruit_MAX31865(D0, D1 , D2, D3);//(16, 5 , 4, 0)
// use hardware SPI, just pass in the CS pin
//Adafruit_MAX31865 thermo = Adafruit_MAX31865(10);
// The value of the Rref resistor. Use 430.0 for PT100 and 4300.0 for PT1000
#define RREF 430.0
// The 'nominal' 0-degrees-C resistance of the sensor
// 100.0 for PT100, 1000.0 for PT1000
#define RNOMINAL 100.0
void setup() {
Serial.begin(115200);
Serial.println("Adafruit MAX31865 PT100 Sensor Test!");
thermo.begin(MAX31865_3WIRE); // set to 2WIRE or 4WIRE as necessary
}
void loop() {
uint16_t rtd = thermo.readRTD();
Serial.print("RTD value: "); Serial.println(rtd);
float ratio = rtd;
ratio /= 32768;
Serial.print("Ratio = "); Serial.println(ratio,8);
Serial.print("Resistance = "); Serial.println(RREF*ratio,8);
Serial.print("Temperature = "); Serial.println(thermo.temperature(RNOMINAL, RREF));
// Check and print any faults
uint8_t fault = thermo.readFault();
if (fault) {
Serial.print("Fault 0x"); Serial.println(fault, HEX);
if (fault & MAX31865_FAULT_HIGHTHRESH) {
Serial.println("RTD High Threshold");
}
if (fault & MAX31865_FAULT_LOWTHRESH) {
Serial.println("RTD Low Threshold");
}
if (fault & MAX31865_FAULT_REFINLOW) {
Serial.println("REFIN- > 0.85 x Bias");
}
if (fault & MAX31865_FAULT_REFINHIGH) {
Serial.println("REFIN- < 0.85 x Bias - FORCE- open");
}
if (fault & MAX31865_FAULT_RTDINLOW) {
Serial.println("RTDIN- < 0.85 x Bias - FORCE- open");
}
if (fault & MAX31865_FAULT_OVUV) {
Serial.println("Under/Over voltage");
}
thermo.clearFault();
}
Serial.println();
delay(1000);
}
I also have used successfully Blynk for projects and can get NodeMCU send datato Blynk Virtual pins. But as soon as I try to integrate the too sets of code the Max31865 fails to take a successful RTD measurement for processing. It is as though the there is a clash in the SPI bus. My code is below.
….any thoughts?
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <Adafruit_MAX31865.h>
Adafruit_MAX31865 thermo = Adafruit_MAX31865(D0, D1 , D2, D3);//(16, 5 , 4, 0)
#define RREF 430.0
#define RNOMINAL 100.0
uint16_t rtd;
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "XXXX";
// Your WiFi credentials.
char ssid[] = "XXX";
char pass[] = "XXX";
BlynkTimer timer;
void myTimerEvent()
{
Serial.print("RTD value: "); Serial.println(rtd);
rtd = thermo.readRTD();
Blynk.virtualWrite(V1, millis() / 1000);
}
void setup()
{
// Debug console
Serial.begin(9600);
Serial.println("Adafruit MAX31865 PT100 Sensor Test!");
thermo.begin(MAX31865_3WIRE); // set to 2WIRE or 4WIRE as necessary
Blynk.begin(auth, ssid, pass);
timer.setInterval(1000L, myTimerEvent);
}
void loop()
{
Blynk.run();
timer.run(); // Initiates BlynkTimer
}
Also, I had tried to use the NODEMCU standard SPI pins (D5,D6,D7,D8) but it was not possible to upload code to the board over USB so I moved to the D0,D1,D2,D3
