Procedure

Expt. : To measure the level using capacitive principle.

Aim: Measure the change in level in terms of change in capacitance.

Step by step Procedure:

1. Study the given diagram completely.
2. Select the height of the tank in centimetres.
3. The value of radius of outer cylinder/pipe for pipe in pipe type probe r2 is fixed 2.5cm.
4. Select the value of radius of inner cylinder/pipe for pipe in pipe type probe r1 in centimetres.
5. Span value will get displayed. Span is 90% of the height of the tank.
6. Select the service for which capacitance probe is to be used.
7. Click on 'Configure System'. It will ask for confirmation.
8. After confirming, select the fluid level from drop down menu for selected service.
9. Enter the calculated user output capacitance in μF. For calculations of output capacitance click on GET FORMULA tab. Using formula calculate the value of the output capacitance for the corresponding level and enter the answer in the box provided (upto 2 decimals with rounding off). Submit the answer using submit button.
10. Study the graphs for RTD performance with different reference resistance values and different materials If your calculation is correct it will be displayed on the screen. Minimum three calculations are necessary to plot the graph. Click on level vs. capacitance graph and level vs. current graph and study them.
11. Click on next set of values. Change the value of r1and repeat steps 7 to 10 Click on graphs and study them.