Procedure

Expt. 1: Static Characteristics of Thermocouple

Aim : Study the change in emf of a thermocouple in response to the process temperature.

Step by step Procedure:

1. Select the type of Thermocouple to be used for experimentation.

2. Select the 'Reference Temp' to set the temperature of reference junction from drop down menu.

3. Click on 'Get Temperature' green color box. The temperature will be displayed for which output (mV) is to be found.

4. Click on 'thermocouple Reference Table' link below the sketch to refer to standard thermocouple charts. From the perticular type of thermocouple chart, find the output millivolt value corresponding to the temperature. Enter it in the box provided and submit.

5. Enter the output millivolt in the answer box. If the answer is correct, it will get indicated in the box below the answer. If not verify it and enter correct output value.If wrong answer is submitted repeatedly for 3 times, the correct answer gets pop-up.

6. Go to step 3. Repeat the procedure at least for 3 times.

7. After finishing the required set of readings 'Plot', 'Next set' and 'Level 2' tabs are enabled. See the graph by clicking on 'Plot' tab.

8. By clicking Next set tab, Repeat the procedure for different types of Thermocouples at various reference temperature values.

9. Click on 'Plot' to see the graphs for comparative study.

10. Study the graphs for RTD performance with different reference resistance values and different materials.

When you click on 'Level 2' tab, you can verify the Dynamic response of the thermocouple.

Expt. 2: Dynamic characteristics

Aim : Study the dynamic response of Thermocouple

In this experiment, the response of thermocouple for a step change in the input is plotted.The maximum temperature the thermocouple attains, is same as the temperature displayed by ' Measurement Tab' in Static part.

Step by step Procedure:

1. The type of thermocouple selected as bare element is by default. It is the same you selected in 'Level 1'. With the standard dimensions considered for bare element, the time constant value will get displayed in the output box. Verify this by using equation given under Get formula tab.

2. Now select the thermocouple dynamic performance with sheath. Select appropriate material and thickness value. The time constant value will get displayed in the output box. Verify this by using equation given under formula tab.

3. Observe the change in the time constant values with different materials with different thickness.

4. Now select the thermocouple dynamic performance with thermowell. Select appropriate material, thickness and filling material. The time constant value will get displayed in the output box when thermowell material, thickness and filling material is selected. Verify this by using equation given under formula tab.

5. Observe the change in the time constant values with different materials with different thickness. Also see the effect of change in filling material.

6. Click on 'Plot' button to observe the dynamic response (Time Vs Temperature).

7. Observe and verify response time of Thermocouple which is generally 5 times the time constant value.

After completion of both the parts, you can proceed to Post Test to find out if you have understood all aspects of the experiment.