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Hi team,
My customer meet a confusions that how to make good use of the heater.
Is there any recommendation for this heating logic? For example, the judgment condition for turning on the heating is whether the detected humidity is greater than a certain value, or whether it is heating at regular intervals, or the dew point humidity is calculated through the temperature value. If the humidity exceeds the dew point, the device start heating?
YOURS
NAN
Hi Nan,
The heater can be switched on briefly to remove condensation from the device that may build at high humidity environments. The heater can also be used to functionally check the integrated temperature sensor. Please see section 3.4 Condensation Removal of the HDC3 Silicon User's Guide for more information.
Best regards,
Jesse
Hi Jesse，
Thanks for your reply.
The customer want to know whether the offset calibration method for temperature and humidity is suitable for HDC2022 shown in the HDC3 user guide.
Please see section 3.4 Condensation Removal of the HDC3 Silicon User's Guide for more information.
YOURS
NAN
Nan -
Yes, the basic method is same. Please see code snippet attached.
//variables to declare
uint16_t HDC2_INT_REG;
uint16_t HDC2_ALL_REG;
uint8_t iBuff_INT_REG2[1];
uint8_t iBuff_ALL_REG[12];
uint16_t HDC2_hum_MSB;
uint16_t HDC2_temp_MSB;
uint16_t HDC2_hum_DEC;
uint16_t HDC2_temp_DEC;
float HDC2_hum_percentage;
float HDC2_temp_celcius;
float HDC2_temp_F;
uint8_t iBuff_HDC2[4];
float HDC2_hum_offset = 0;
float HDC2_hum_offset_2 = 0;
uint8_t iBuff_TMP[2];
float TMP_BYTES;
int val2 = 0; //variable for triggering read when data is ready from DRDY/INT pin on HDC2080
uint8_t iBuff_INT_REG[1];
float temp_slope;
float hum_slope;
float START_TEMP = 0;
float AMB_TEMP = 0;
float TEMP_RISE = 0;
float START_HUM = 0;
float START_TEMP_2 = 0;
float AMB_TEMP_2 = 0;
float TEMP_RISE_2 = 0;
float START_HUM_2 = 0;
int i = 1;
int j = 1;
int count1 = 0;
int count2 = 0;
//LUT example, works on HDC2 with 0.31" PCB and cutout around part
float LUT_temp_humidity_HDC2 [9][4] =
{
//30 25 20 15
{43.50, 43.50, 43.50, 43.50}, //60 -> 65
{43.50, 43.50, 43.50, 43.50}, //55 -> 60
{43.50, 43.50, 43.50, 43.50}, //50 -> 55
{43.50, 43.50, 43.50, 43.50}, //45 -> 50
{44.75, 44.75, 44.75, 44.75}, //40 -> 45
{44.75, 44.75, 44.75, 44.75}, //35 -> 40
{44.75, 44.75, 44.75, 44.75}, //30 -> 35
{44.75, 44.75, 44.75, 44.75}, //25 -> 30
{44.75, 44.75, 44.75, 44.75} //20 -> 25
};
case '1':
{
float from_LUT = 0; //***
int temp_index = 0;
int humidity_index = 0;
Serial.println("HDC2 (on LTD BOARD) %RH OFFSET CORRECTION");
digitalWrite(LED, HIGH); // turns red LED on solid (indicating calibration routine is running)
digitalWrite(LED2, LOW); // turns off green LED (for heartbeat in normal operation):
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x0F); // Register 0x0F
Wire.write(0x01); // HDC2 start conversion (0x01) 14 bit
Wire.endTransmission(); // stop transmitting
delayMicroseconds(1500); // delay set for 14 bit conversion time for temp and humidity together - typical should be ~1270uSec
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x04); // pointer
Wire.endTransmission(); // stop transmitting
Wire.requestFrom(0x41, 1, 1); // request 1 bytes from HDC2 device, register 0x04 (should be 0x80)
Wire.readBytes (iBuff_INT_REG, 1);
HDC2_INT_REG = iBuff_INT_REG[0];
if (HDC2_INT_REG == 0x80)
{
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x00); // pointer
Wire.endTransmission(); // stop transmitting
Wire.requestFrom(0x41, 4, 1); // request 4 bytes from HDC2 device, registers 0x00 through 0x03
while (Wire.available())
{
Wire.readBytes(iBuff_HDC2, 4);
HDC2_temp_MSB = (iBuff_HDC2[1] << 8); // shift left
HDC2_temp_DEC = (HDC2_temp_MSB + iBuff_HDC2[0]); // get value for calculation, made from iBuff index array values 0 and 1 for temp reading.
HDC2_temp_celcius = ((float)(HDC2_temp_DEC) / 65536) * 165 - 40.62; // do math according to the HDC2080 datasheet
// HDC2_temp_celcius = ((float)(HDC2_temp_DEC) / 65536) * 165 - 40; // do math according to the HDC2010, HDC2021, HDC2022 datasheets, comment in when using those devices, comment out line above
START_TEMP_2 = HDC2_temp_celcius;
AMB_TEMP_2 = START_TEMP_2;
Serial.print(",");
Serial.print("AMBIENT TEMP :");
Serial.print(AMB_TEMP_2); // print out start temperature to terminal
Serial.println(",");
HDC2_hum_MSB = iBuff_HDC2[3] << 8; // shift left
HDC2_hum_DEC = (HDC2_hum_MSB + iBuff_HDC2[2]); // get value for calculation, made from iBuff index array values 3 and 2 for humidity reading.
HDC2_hum_percentage = ((float)(HDC2_hum_DEC) / 65536) * 100; // do math according to the HDC2 datasheet
START_HUM_2 = HDC2_hum_percentage;
Serial.print("AMBIENT HUMIDITY :");
Serial.print(START_HUM_2); // print out %RH value to terminal
Serial.println(",");
//temp col index 15, 21, 25, 30C
// get the temp index
temp_index = 0;
if ((HDC2_temp_celcius > 0) && (HDC2_temp_celcius <= 15))
temp_index = 0;
else if ((HDC2_temp_celcius > 15) && (HDC2_temp_celcius <= 21))
temp_index = 1;
else if ((HDC2_temp_celcius > 21) && (HDC2_temp_celcius <= 25))
temp_index = 2;
else if ((HDC2_temp_celcius > 25) && (HDC2_temp_celcius <= 30))
temp_index = 3;
// humidity index - 60,55,50,45,40,35,30,25,20
// find humidy index in LUT.
humidity_index = int((HDC2_hum_percentage - 20) / 5);
if (humidity_index > 8)
humidity_index = 8;
if (humidity_index < 0)
humidity_index = 0;
humidity_index = 8 - humidity_index;
//look up the table to set the threshold
from_LUT = LUT_temp_humidity_HDC2[humidity_index][temp_index];
Serial.println("Calculated Indexes: ");
Serial.print("Humidity Index :");
Serial.println(humidity_index);
Serial.print("Temperature Index :");
Serial.println(temp_index);
Serial.print("Look up table value (in C) :");
Serial.println(from_LUT);
// Serial.println(",");
}
}
// turn heater on
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x0E); // Register 0x0E
Wire.write(0x08); // HDC2 heater bit on
Wire.endTransmission(); // stop transmitting
do {
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x0F); // Register 0x0F
Wire.write(0x01); // HDC2 start conversion (0x01) 14 bit
Wire.endTransmission(); // stop transmitting
delayMicroseconds(1500); // delay set for 14 bit conversion time for temp and humidity together - typical should be ~1270uSec
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x04); // pointer
Wire.endTransmission(); // stop transmitting
Wire.requestFrom(0x41, 1, 1); // request 1 bytes from HDC2 device, register 0x04 (should be 0x80)
Wire.readBytes (iBuff_INT_REG, 1);
HDC2_INT_REG = iBuff_INT_REG[0];
if (HDC2_INT_REG == 0x80)
{
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x00); // pointer
Wire.endTransmission(); // stop transmitting
Wire.requestFrom(0x41, 4, 1); // request 4 bytes from HDC2 device, registers 0x00 through 0x03
while (Wire.available())
{
Wire.readBytes(iBuff_HDC2, 4);
HDC2_temp_MSB = (iBuff_HDC2[1] << 8); // shift left
HDC2_temp_DEC = (HDC2_temp_MSB + iBuff_HDC2[0]); // get value for calculation, made from iBuff index array values 0 and 1 for temp reading.
HDC2_temp_celcius = ((float)(HDC2_temp_DEC) / 65536) * 165 - 40.62; // do math according to the HDC2080 datasheet
// HDC2_temp_celcius = ((float)(HDC2_temp_DEC) / 65536) * 165 - 40; // do math according to the HDC2010, HDC2021, HDC2022 datasheets, comment in when using those devices, comment out line above
// Serial.print(",");
Serial.print(HDC2_temp_celcius); // print out temperature to terminal
Serial.print(",");
TEMP_RISE_2 = HDC2_temp_celcius - AMB_TEMP_2;
Serial.print(TEMP_RISE_2); // print out temperature to terminal
Serial.print(",");
temp_slope = (START_TEMP_2 - HDC2_temp_celcius) / (count1 - i) ;
i++;
count1++;
START_TEMP_2 = HDC2_temp_celcius;
HDC2_hum_MSB = iBuff_HDC2[3] << 8; // shift left
HDC2_hum_DEC = (HDC2_hum_MSB + iBuff_HDC2[2]); // get value for calculation, made from iBuff index array values 3 and 2 for humidity reading.
HDC2_hum_percentage = ((float)(HDC2_hum_DEC) / 65536) * 100; // do math according to the HDC2 datasheet
// HDC2_hum_offset = HDC2_hum_percentage;
// HDC2_hum_offset = HDC2_hum_percentage / 2;
HDC2_hum_offset_2 = HDC2_hum_percentage;
hum_slope = (START_HUM - HDC2_hum_percentage) / (count2 - j) ;
j++;
count2++;
START_HUM_2 = HDC2_hum_percentage;
Serial.print(HDC2_hum_offset_2); // print out %RH offset to terminal
Serial.print(",");
hum_slope = 0 - hum_slope; // make hum_slope a positive value
Serial.println(temp_slope);
Serial.print(",");
}
}
} while (TEMP_RISE_2 <= from_LUT); //HDC2080 on LTD with cutout
//Reset variables & counters for next time using the calibration routine
i = 1;
j = 1;
count1 = 0;
count2 = 0;
START_TEMP_2 = 0;
Serial.println("DONE"); // Print humidity board header
// turn heater off
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x0E); // Register 0x0E
Wire.write(0x00); // HDC2 heater bit off
Wire.endTransmission(); // stop transmitting
delay(50);
// enable DRDY/INT pin feature
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x07); // Register 0x07
Wire.write(0x80); // HDC2 DRDY/INT setting
Wire.endTransmission(); // stop transmitting
delay(2);
// config interrupt
Wire.beginTransmission(0x41); // transmit to HDC2 device address 0x41
Wire.write(0x0E); // Register 0x0E
Wire.write(0x06); // HDC2 config (for one shot)
Wire.endTransmission();
digitalWrite(LED, LOW); // turns red LED off (indicating calibration routine is complete)
delay(2);
break;
}
Hi Josh,
Thanks for your reply. I will share the code with customer.
YOURS
NAN