Hach 3700 Series Basic User Manual page 21

6. Hold the dry sensor in the air and push ENTER.
7. Review the calibration result:
• Pass—the zero point is set.
• Fail—the value is outside of accepted limits. Make sure the sensor is dry and repeat the zero
calibration procedure. Make sure that the cause is not the digital extension cable or a lot of
electronic noise.
8. If the calibration passed, push ENTER to continue.
9. For the sc100 controller, go to step 12.
10. If the option for operator ID is set to Yes in the Calibration Options menu, enter an operator ID.
Refer to Change calibration options
11. On the New Sensor screen, select whether the sensor is new:
Option Description
Yes The sensor was not calibrated previously with this controller. The days of operation and previous
calibration curves for the sensor are reset.
No The sensor was calibrated previously with this controller.
12. Proceed to the calibration with a reference solution or process sample.
Calibration with a reference solution
Calibration adjusts the sensor reading to match the value of a reference solution. Use a reference
solution that is at the same value or higher than the expected measurement readings.
Note: If the sensor is being calibrated for the first time, be sure to complete the zero calibration first.
1. Thoroughly rinse the clean sensor in deionized water.
2. Put the sensor in the reference solution. Support the sensor so that it does not touch the
container. Make sure that there is at least 2 inches of space between the sensor and the sides of
the container (Figure
Figure 12 Sensor in reference solution
3. Wait for the sensor and solution temperature to equalize. This can take 30 minutes or more if the
temperature difference between the process and reference solution is significant.
4. Push the MENU key and select Sensor Setup, [Select Sensor], Calibrate.
5. Select Sample Cal and push ENTER.
6. For the sc200 or sc1000 controller, select the calibration for the specified parameter and push
ENTER:
• Conductivity—Cond Cal
• TDS—TDS Cal
• Salinity—Cond Cal
• Concentration—Conc Cal or Cond Cal
Note: Refer to the sensor configuration menu if the option that is necessary is not shown.
7. If the passcode is enabled in the security menu for the controller, enter the passcode.
on page 24.
12). Stir the sensor to remove bubbles.
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