Interfacing the NEG RGB LCD to display thermocouple readings from MAX 31855

[odoyo]

can anybody help with the sketch for interfacing the RGB LCD shield with the MAX 31855 amplifier to get thermocouple readings using a stand alone arduino uno.

[adafruit_support_bill]

What help do you need? Post your current sketch and describe what it does or doesn't do for you.

[odoyo]

I was just using the example for the max 31855 to get the thermocoulple reading and was getting weird results of like 6 degrees and -200 while I'm at a room temperature of about 24.

Code: Select all

#include "Adafruit_MAX31855.h"

int thermoDO = 3;
int thermoCS = 4;
int thermoCLK = 5;

Adafruit_MAX31855 thermocouple(thermoCLK, thermoCS, thermoDO);
 
void setup() {
  Serial.begin(9600);
 
  Serial.println("MAX31855 test");
  // wait for MAX chip to stabilize
  delay(500);
}

void loop() {
  // basic readout test, just print the current temp
   Serial.print("Internal Temp = ");
   Serial.println(thermocouple.readInternal());

   double c = thermocouple.readCelsius();
   if (isnan(c)) {
     Serial.println("Something wrong with thermocouple!");
   } else {
     Serial.print("C = ");
     Serial.println(c);
   }
   //Serial.print("F = ");
   //Serial.println(thermocouple.readFarenheit());

   delay(1000);

is something wrong with the library or is their something i need to change?

[adafruit_support_bill]

The thermocouple amplifier is very sensitive and the readings can be affected by electrical noise. Keep the thermocouple probe away from other wiring and use the shortest wire possible.

[adafruit_support_rick]

Looks like there was a bug in the 31855 library.

Delete the old version and download the new version. See if that helps.

[adafruit_support_bill]

Looks like there was a bug in the 31855 library.

That affected readings below 0C (32F)

[Scirocco]

Hello,

I'm getting very similar results to the OP. -2000 deg C, to about 10 deg C at room temperature. It seems like it's discontinuous between -2000 to 6 deg C, switching back and forth rapidly. Was there ever a resolution to the problem?

Scirocco

[adafruit_support_bill]

The amp is very sensitive to noise, which can result in unstable readings. You can try putting a 0.1uF or 0.01uF capacitor in parallel with the thermocouple probe in the screw-terminal block to tame the noise.

[adafruit]

Hello,

I'm getting very similar results to the OP. -2000 deg C, to about 10 deg C at room temperature. It seems like it's discontinuous between -2000 to 6 deg C, switching back and forth rapidly. Was there ever a resolution to the problem?

Scirocco

make sure to download the latest library - we had a few bugs with negative temp readings. delete the old library completely