B&B Electronics I-7011 Benutzerhandbuch

I-7011, I-7018 User Manual

Rev:B1.0

To measure the Seebeck voltage directly is not available

because we must first connect a voltmeter to the thermocouple,

and the voltmeter leads themselves create a new thermoelectric

circuit. Therefore we need to eliminate the junction thermoelectric

to measure the correct Seebeck voltage, and this is called “Cold

Junction Compensation”.

For most thermocouples, the Seebeck voltage is 0V while

in 0°C. One simple way to cancel the junction voltage is to put the

junction into 0°C enviroment and the junction voltage is 0V. Nor-

mally, this is not a good method for most application. Typical method

is to measure the junction temperature by thermistor, and measure

the junction voltage from the junction temperature. Then we may

get the Seebeck voltage from measured thermocouple voltage and

junction voltage, and we may calculate the temperature from the

Seebeck voltage.