Hello, I'm working on a project utilizing 6, T-type thermocouples for ground temperature measurements over time. My interface is the Ocean Controls Thermocouple Multiplexer Shield (KTA-259T) mounted atop an arduino Metro from Adafruit.
The issue is the serial plotter does not display the temperature data graphs. It will display the X axis title bar at the very top of the window and the Y axis is not displayed. The data is displayed in the serial monitor they way i'd expect.
I've read numerous posts about others having similar issues, typically with not using Serial.print(' ') or Serial.println(""), but it seems to be correct in my code to the best of my knowledge. Appreciate any input you may have here...i'm sure this is a simple code fix. The code is a sample code from the Ocean Controls website.
[code]
// Assumes 20 MHz or less clock. Insert NOPs for faster operation.
// Pinout for Ocean Design's Thermocouple Multiplexer Shield
#define PINEN 7 // TC Mux Enable pin
#define PINA0 4 // TC Mux Address 0 pin
#define PINA1 5 // TC Mux Address 1 pin
#define PINA2 6 // TC Mux Address 2 pin
#define PINSO 12 //TC ADC Slave Out pin (MISO)
#define PINSC 13 //TC ADC Serial Clock (SCK)
#define PINCS 9 //TC ADC Chip Select
#define SHORT -1001
#define OPEN -1000
volatile int tcTemp[9]; // in quarter deg. C, tcTemp[8] is the interal reference temp, disable IRQ's to access these
int readSPI() {
word v = 0;
for (byte i = 16; i != 0; i--) {
v <<= 1;
digitalWrite(PINSC, HIGH);
// 100nS min. delay implied
v |= digitalRead(PINSO);
digitalWrite(PINSC, LOW); // request next serial bit
// 100nS min. delay implied
}
return v;
}
void tcTempSetup() {
pinMode(PINEN, OUTPUT);
pinMode(PINA0, OUTPUT);
pinMode(PINA1, OUTPUT);
pinMode(PINA2, OUTPUT);
pinMode(PINSO, INPUT);
pinMode(PINCS, OUTPUT);
pinMode(PINSC, OUTPUT);
digitalWrite(PINEN, HIGH); // enable the mux all the time
digitalWrite(PINSC, LOW); // put clock in low
digitalWrite(PINCS, LOW); // stop conversion, start serial interface
// Timer0's overflow is used for millis() - setup to interrupt
// in the middle and call the "Compare A" function below
OCR0A = 0x80;
TIMSK0 |= _BV(OCIE0A);
}
void setup() {
Serial.begin(9600);
tcTempSetup();
}
// Interrupt is called every millisecond
SIGNAL(TIMER0_COMPA_vect) {
static byte ms = 0;
static byte ch = 0;
if (ms == 0) {
// select the thermocouple channel on the mux
digitalWrite(PINA0, ch & 1);
digitalWrite(PINA1, ch & 2);
digitalWrite(PINA2, ch & 4);
// ... wait a while for the capacitor on the ADC input to charge (< .1 mS actually needed)
} else if (ms == 5) {
// begin conversion
digitalWrite(PINCS, HIGH);
// ... wait 100 mS for conversion to complete
} else if (ms == 105) {
// stop conversion, start serial interface
digitalWrite(PINCS, LOW);
// 100nS min. delay implied
int rawTC = readSPI();
int rawIT = readSPI();
int tempC = rawTC / 4;
if (rawTC & 1) {
if (rawIT & 1) {
tempC = OPEN;
}
if (rawIT & 6) {
tempC = SHORT;
}
}
tcTemp[ch] = tempC;
if (++ch == 8) {
tcTemp[8] = rawIT / 64; // internal temperature reduced to quarter degree C
ch = 0;
}
ms = 255; // ++ will make this 0
}
ms++;
}
void loop() {
for (byte j = 0; j < 9; j++) {
Serial.print((word)j);
Serial.print('=');
// access thermocouple readings with interrupts disabled to prevent 'shearing'
noInterrupts();
int t = tcTemp[j];
interrupts();
if (t == OPEN) {
Serial.print("OPEN");
} else if (t == SHORT) {
Serial.print("SHORT");
} else {
Serial.print(t / 4);
}
Serial.print(' ');
}
Serial.println("");
delay(1000); // delay(1000) milleseconds, set this for print time;
}
[/code]
