Pt100 rtd sensor with Max3165 and nodemcu givin random value
Posted: Mon Jan 07, 2019 9:02 amthe sensor gives proper values when in use arduino uno.
but using nodemcu it gives 1 correct result then 3 incorrect values
This is the code i have used
i have connected jumper wire for 3 wire rtd sensor on max31865
Connection
max31865 nodemcu
vin 3.3
gnd gnd
3v3 nc
clk d5
sdo d6
sdi d7
cs d8
drdy nc
but using nodemcu it gives 1 correct result then 3 incorrect values
This is the code i have used
i have connected jumper wire for 3 wire rtd sensor on max31865
Connection
max31865 nodemcu
vin 3.3
gnd gnd
3v3 nc
clk d5
sdo d6
sdi d7
cs d8
drdy nc
Code: Select all
#include <SPI.h>
/***************************************************
This is a library for the Adafruit PT100/P1000 RTD Sensor w/MAX31865
Designed specifically to work with the Adafruit RTD Sensor
----> https://www.adafruit.com/products/3328
This sensor uses SPI to communicate, 4 pins are required to
interface
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!
Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, all text above must be included in any redistribution
****************************************************/
#include <Adafruit_MAX31865.h>
// Use software SPI: CS, DI, DO, CLK
Adafruit_MAX31865 max1 = Adafruit_MAX31865(15, 13, 12, 14);
// use hardware SPI, just pass in the CS pin
//Adafruit_MAX31865 max1 = 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!");
SPI.begin(); /* begin SPI */
max1.begin(MAX31865_3WIRE); // set to 2WIRE or 4WIRE as necessary
}
void loop() {
uint16_t rtd = max1.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(max1.temperature(RNOMINAL, RREF));
// Check and print any faults
uint8_t fault = max1.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");
}
max1.clearFault();
}
Serial.println();
delay(1000);
}
)