Measuring two temps

Hopefully, you do it before you need to replace a probe.

With minor changes, the old emonTx ‘Temperature Search’ sketch works for the emonTH:

/*******************************************************************************************
*                                                                                          *
*                         Temperature Search for emonTH V2                                 *
*                                                                                          *
*******************************************************************************************/


// Connect Sensor as here: https://wiki.openenergymonitor.org/index.php/EmonTH_V1.5#External_DS18B20_Temperature_Sensor_Connections
// Test one sensor at a time, restart this sketch for each, and note the serial number.
//
// THIS SKETCH REQUIRES:

// Libraries in the standard arduino libraries folder:
//
//	- OneWire library	http://www.pjrc.com/teensy/td_libs_OneWire.html
//	- DallasTemperature	http://download.milesburton.com/Arduino/MaximTemperature

#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 17
#define TEMPERATURE_PRECISION 12
#define DS18B20_PWR   5

// Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
OneWire oneWire(ONE_WIRE_BUS);

// Pass our oneWire reference to Dallas Temperature. 
DallasTemperature sensors(&oneWire);

void setup()
{
  delay(1000);
  Serial.begin(115200);
  Serial.println("Temperature search");
  Serial.println("waiting 6 seconds before printing");
  delay(6000);

  pinMode(DS18B20_PWR,OUTPUT);
  digitalWrite(DS18B20_PWR, HIGH); delay(50);
  sensors.begin();
  
  DeviceAddress tmp_address;
  int numberOfDevices = sensors.getDeviceCount();
  
  for(int i=0;i<numberOfDevices; i++)
  {
    oneWire.search(tmp_address);
    printAddress(tmp_address);
    Serial.println();
  }
}

void loop()
{ 
 
}

void printAddress(DeviceAddress deviceAddress)
{
  Serial.print("{ ");
  for (uint8_t i = 0; i < 8; i++)
  {
    // zero pad the address if necessary
    Serial.print("0x");
    if (deviceAddress[i] < 16) Serial.print("0");
    Serial.print(deviceAddress[i], HEX);
    if (i<7) Serial.print(", ");
    
  }
  Serial.print(" }");
}