10. When you are ready to start a pH measurement, put the pH probe in whatever you are going to be measuring. Allow the pH reading to stabilize, you will see it blinking just below the x axis. When you are ready to start collecting data then click on Start. Data collection will stop automatically at the end of the time set on the x axis. Data collection can be stopped manually by clicking on Stop.
1. Attach pH probe to ULI in either DIN 1 or DIN 2. 2. Attach the computer cable and the power cord to the ULI 3. Connect the computer cable to the modem port on the back of the Mac. 4. The ULI must be turned on before loading the Data Logger program. Turn the red ON/OFF switch to ON. You should see the red and green LEDs should light up. 5. Load Vernier Logger program. It should be in the folder named Vernier on the hard drive. You will see a screen that looks like this. 6. After the program has been loaded, pull down the Collect menu and click on Select Probes. Depending on which DIN your pH probe is plugged into, click OFF the one you are not going to be using. 7. Also under the Collect menu are Data Rate. Click on it to change the number of data points per second or the time for one point. 8. Then go back to the Collect menu and click on Calibrate, then Calibrate Now. Follow the directions given for calibrating the pH probe. When finished, pull down the File menu and click on Save Calibration. Save it on your disk and give it a name that identifies it as a pH calibration and its date. 9. Next, go to the Display menu and click on Axes. Set the x axis for the desired time, in seconds. Set the y axis for the best pH range. For example, if you know that the pH will not be going over 10, then set the pH for a maximum of 11. Click on Units to change the time from seconds to minutes or hours.
11. If the scale needs to be changed, then go back to item #7 and redo the x and/or y axes.
12. The data and /or graph can be saved, if desired, or printed out. The usual save and print functions under the File menu are used. If you are going to be importing the data into Kalediograph, then save the data as a text file.
Send questions, comments or suggestions to
Gwen Sibert, at the
Roanoke Valley Governor's School
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