Introduction

The ADS1118 is a small, low power, 16-bit ADC with a built-in temperature sensor. It is ideally suited for measuring thermocouples with cold junction compensation.

Also check out the Reclaimer Labs Thermocouple library and the Remote Thermal Monitor board.

Example Usage

Usually, you will want to use the readADC_Diff_0_1_mV() and readADC_Diff_2_3_mV() functions with the readTemp_C() function. This provides everything you need to accurately measure temperature with a thermocouple.

const uint16_t pin_CS0 = A2;
ReclaimerLabs_ADS1118 therm01(pin_CS0);

void setup() {
    // set chip select pins high
    pinMode(pin_CS0, OUTPUT);
    digitalWrite(pin_CS0, HIGH);
    
    therm01.setGain(GAIN_SIXTEEN);
}

void loop() {
	float temp_mV, tempRef_C, temp_C;
	int32 error_code;
	temp_mV = therm01.readADC_Diff_0_1_mV();
    error_code = ReclaimerLabs_Thermocouple::calc_temp(TYPE_K, temp_mV, tempRef_C, &temp_C);
}

Other functions

uint16_t readADC_SingleEnded(uint8_t channel);

Takes in a channel number (0 to 3) and returns a 16-bit ADC reading referencing GND and VDD as full-scale.

int16_t readADC_Differential_0_1(void);

Returns the raw 16-bit ADC value of the differential voltage of channel 0 minus 1.

int16_t readADC_Differential_2_3(void);

Returns the raw 16-bit ADC value of the differential voltage of channel 2 minus 3.

int16_t readTemp_Raw(void);

Returns the raw 14-bit ADC value of the on-chip temperature sensor. Negative numbers use twos complement. One 14-bit LSB equals 0.03125 degrees C.

void setGain(adsGain_t gain);

setGain() and getGain() use the enum adsGain_t.

• GAIN_TWOTHIRDS, full-scale = 6.144 V
• GAIN_ONE, full-scale = 4.096 V
• GAIN_TWO, full-scale = 2.048 V
• GAIN_FOUR, full-scale = 1.024 V
• GAIN_EIGHT, full-scale = 0.512 V
• GAIN_SIXTEEN, full-scale = 0.256 V

Questions and Comments

If you have questions or comments, you can email me directly at [email protected].