Materials:
CBL system
TI-83 Plus graphing calculator
CHEMBIO program
Vernier Conductivity Probe
Vernier adapter cable
Calculator-to-CBL link cable
Texas Instruments AC 9201 adapter (or use batteries)
Tissues or paper towels
500 mg/L TDS standard solution
distilled or de-ionized water
cup attached to a rod

Testing Procedure:
1. Plug the Conductivity Probe into the adapter cable in Channel 1 of the CBL.
2. Set the switch on the probe box to the 0-2000 µS range (2000 µS = 1000 mg/L TDS).
3. Use the link cable to connect the CBL System to the TI Graphing Calculator.
4. Turn on the CBL unit and the calculator.
5. Start the CHEMBIO program and proceed to the MAIN MENU.
6. Select SET UP PROBES from the MAIN MENU.
7. Enter 1 as the number of probes.
8. Select CONDUCTIVITY from the SELECT PROBE menu.
9. Enter 1 as the channel number.
10. Select PERFORM NEW from the CALIBRATION menu.
11. Follow the directions on the calculator screen to allow the system to warm up, then press ENTER
12. Perform the first calibration point with the probe in the air (e.g., out of any solution).
13. When the readings displayed on the CBL screen stabilize, press TRIGGER on the CBL.
14. Enter 0 on the calculator.Place the Conductivity Probe into the 500 mg/L TDS standard solution. The hole near the tip of the probe should be covered completely.
15. Wait for the readings displayed on the CBL to stabilize and press TRIGGER.
16. Enter 500(the concentration in mg/L) on the calculator and press ENTER to return to the MAIN MENU.
17. Set up the calculator and CBL for data collection.
18. Select COLLECT DATA from the MAIN MENU.
19. Select SINGLE POINT from the DATA COLLECTION menu
20. Rinse the probe tip with distilled water.
21.Place the tip of the electrode into the stream, or into a cup with sample water from the stream. The hole near the tip of the probe should be completely covered.
22. When the reading displayed on the CBL screen has stabilized, press ENTER to begin sampling. Important: Leave the probe tip submerged while data is being collected during the next 25 seconds.
23.After 25 seconds, the TDS value will appear on the calculator screen.
24. Record this value on the Data & Calculations sheet (round to the nearest 1 mg/L TDS).
25. Press ENTER then select YES to repeat the measurement.
26. Press ENTER to take another reading.
27. Record this value on the Data & Calculations sheet (round to the nearest 1 mg/L TDS).NOTE:
28. If your readings are less than 100mg/L, recalibrate the probe for a lower range setting at 0-100 mg/L for more accurate results. To do this, change the setting on the probe bow to 0-200 µS and repeat Steps 5-28. Use the stored 100-mg/L TDS calibration, or calibrate with a 50 mg/L TDS standard provided by your instructor.