multiple MAX6675 reads only 32 F or 0 C MEGA2560

Other Hardware Sensors
1

I'm in the process of building a multiple burner melting furnace, using servos to control the fuel feed based on furnace temperatures

I have everything working except getting usable readings out of the tcouples using max6675 and a Mega2560

below is the relevant code

//sketch tilting furnace
#include "Servo.h"
#include "max6675.h"

// Declare the max6675 thermocouple
//CRUCIBLE max6675
int tcSO = 8;  // 6675 Serial Output     Crucible
int tcCS = 9;   // 6675 Chip Select      Crucible
int tcCLK = 10;    // 6675  Clock         Crucible
float DegreesF_cf = 0;   // CRUCIBLE TEMP
float cfSETP;         // CRUCIBLE SETPOINT
MAX6675 tc(tcCLK, tcCS, tcSO );

// TILT max6675
int tcFSO = 28;  // 6675 Serial Output           Tilting
int tcFCS = 29;   // 6675  Chip Select            Tilting
int tcFCLK = 30;    // 6675  Tilting Clock Pin    Tilting
float DegreesF_tf = 0;   // TILT TEMP
float tfSETP;         // TILT SETPOINT
MAX6675 tcF(tcFCLK, tcFCS, tcFSO );

void loop()
{
DegreesF_tf = tcF.readFahrenheit();
delay(100);
DegreesF_cf = tc.readFahrenheit();
delay(100);

This is a typical application of the sensors

{ // Crucible burner control

      if  (digitalRead(CPBS) == LOW) {
        digitalWrite(CPV, LOW);
      } // pilot switch activates pilot
      cfSETP = 1500; [b]DegreesF_cf = tc.readFahrenheit();[/b]
      { if   (digitalRead(COBS) == LOW) //oil switch enables oil burner opeation based on tcouple
        { if  (cfSETP - DegreesF_cf > 100)COservo.write(40);// crucible oil control
          else {
            { if (cfSETP - DegreesF_cf < 100)COservo.write(((cfSETP - DegreesF_cf) / 4) + 10);

              else {
                if (cfSETP - DegreesF_cf <= 0)COservo.write (10);

the "servo" goes to 4o
the "degreesF_cf" goes to 32

Do the Max6675s need to be "ATTACHED" as the servos did or does declaring "INT" accomplish that????
Do the pins need to be set as "INPUT" etc.

thanks in advance

Art B

2

Please edit your post to add code tags, as described in "How to use this forum". Be sure to post the complete code, not a fragment.

You should get one sensor working before adding anything else.