Hach-Lange 1200-S sc - Manual (Page 19)

Operation
17
5.6 Sensor calibration (pH)
The electrode is calibrated in the factory and is very stable. As a rule, calibration is
only necessary after several weeks or after the electrode of the probe is changed.
For continued retention of the measuring accuracy and reproducibility, the
manufacturer recommends the replacement of the electrode after approx. one
year of operation.
Calibrate the sensor
• after the electrode of the probe is changed,
• as required or
• in accordance or agreement with the authorities.
Note: If you use alkaline buffer
solutions, use them quickly. They
absorb carbon dioxide from of the
air and are therefore relatively
unstable.
The calibration comprises one or two sample or buffer solutions with defined pH
value and the comparison of the values displayed with the values for the sample
or buffer solution. The calibration is straightforward for the user to perform.
5.6.1 Calibration using a buffer solution
1. Ensure the correct buffers solutions are selected in the SENSOR
SETUP=>CONFIGURE=>SELECT BUFFER menu.
2. Remove the sensor from the flow of product and clean it.
3. Place the sensor and the buffer solution at the same temperature.
4. Hold the sensor in the buffer solution for 10 minutes and accept to continue.
5. Accept when the measured value has stabilised.
The sensor detects the buffer solution and makes all the necessary settings
automatically.
5.6.2 Calibration using two buffer solutions
The calibration is performed in exactly the same way for the calibration with one
buffer solution. In addition, the controller prompts you to:
1. Clean the sensor and hold it in the second buffer solution for 10 minutes.
The sensor detects the buffer solution and makes all the necessary settings
automatically.