Thermocouple Measurement and Reference Junction Temperatures
Calculate the amount of voltage “seen” by the voltmeter given the following measurement and reference junction temperatures:
- T1 = 589 oF ; T2 = 63 oF ; T3 = 70 oF ; Vmeter = __________ mV
- T1 = 821 oF ; T2 = 69 oF ; T3 = 73 oF ; Vmeter = __________ mV
- T1 = 1524 oF ; T2 = 91 oF ; T3 = 105 oF ; Vmeter = __________ mV
- T1 = 1922 oF ; T2 = 102 oF ; T3 = 135 oF ; Vmeter = __________ mV
Answer :
All answers based on ITS-90 thermocouple table values:
- T1 = 589 oF ; T2 = 63 oF ; T3 = 70 oF ; Vmeter = 0.463 mV
- T1 = 821 oF ; T2 = 69 oF ; T3 = 73 oF ; Vmeter = 0.953 mV
- T1 = 1524 oF ; T2 = 91 oF ; T3 = 105 oF ; Vmeter = 3.378 mV
- T1 = 1922 oF ; T2 = 102 oF ; T3 = 135 oF ; Vmeter = 5.294 mV
Note: all temperatures at T2 are irrelevant because this is a junction between similar metals (type B wires connecting to corresponding type B wires). The reference (cold) junction is where the type B wires connect to copper, at temperature T3.