Hach 3700 Série Manuel D'utilisation De Base page 18

instrument. Be sure to enter the T-factor in the Configure menu for accurate temperature
compensation.
During calibration, data is not sent to the datalog. Thus, the datalog can have areas where the data is
intermittent.
6.4.2 Zero calibration procedure
Use the zero calibration procedure to define the unique zero point of the conductivity sensor. The
zero point must be defined before the sensor is calibrated for the first time with a reference solution
or process sample.
1. Remove the sensor from the process. Wipe the sensor with a clean towel or use compressed air
to make sure the sensor is clean and dry.
2. Push the MENU key and select Sensor Setup, [Select Sensor], Calibrate.
3. Push ENTER to select Zero Cal.
4. If the passcode is enabled in the security menu for the controller, enter the passcode.
5. Select the option for the output signal during calibration:
Option Description
Active The instrument sends the current measured output value during the calibration procedure.
Hold The sensor output value is held at the current measured value during the calibration procedure.
Transfer A preset output value is sent during calibration. Refer to the controller user manual to change the
preset value.
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.
6.4.3 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
18 English
on page 21.
10). Stir the sensor to remove bubbles.