Procedure

Expt. 1: Static Characteristics of RTD

Aim: Study the change in resistance of RTD probe depending on the process temperature.

Step by step Procedure:

1. Select the material of RTD you want to use. Temperature coefficient (α) for the same will be displayed on the screen. Note this value.
2. Click on ' R0' to get the value of R0 for selected RTD. Note the same.
3. Click on 'Get Temp'. The temperature for which Rt is to be found will be displayed.
4. Using formula calculate the value of Rt and enter the answer in the box provided (upto 2 decimals with rounding off). Submit the answer using submit button.
5. If your calculation is correct, go to step 3. Repeat the procedure min 3 times.
6. If your calculation is wrong, you will be asked to repeat the same. Please refer to GET FORMULA tab and verify your calculations.
7. After finishing minimum 3 set of correct readings, you can see the graph by clicking on 'Plot'.
8. When the graph is displayed click Next tab to repeat the procedure with different reference resistance(R0) value and with different materials.
9. Minimum 3 calculations are necessary to plot the graph.
10. Study the graphs for RTD performance with different reference resistance values and different materials

Expt. 2: Dynamic characteristics

Aim: Study the dynamic response of RTD probe

In this experiment, Platinum RTD is used for calculating the time constant values. The response of RTD for a step change in the input is plotted. The maximum temperature the RTD attains, is same as the temperature displayed by 'GET Temp' tab.

Step by step Procedure:

1. Select the RTD as bare element (make it on). 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 RTD 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 RTD 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 RTD 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.