Hach 8398 Serie Manual Del Usuario página 8

4.3 Calibrate the sensor
Fluid pressure hazard. Removal of a sensor from a pressurized vessel can be dangerous. Reduce
the process pressure to below 7.25 psi (50 kPa) before removal. If this is not possible, use extreme
caution. Refer to the documentation supplied with the mounting hardware for more information.
Chemical exposure hazard. Obey laboratory safety procedures and wear all of the personal protective
equipment appropriate to the chemicals that are handled. Refer to the current safety data sheets
(MSDS/SDS) for safety protocols.
Chemical exposure hazard. Dispose of chemicals and wastes in accordance with local, regional and
national regulations.
4.3.1 About sensor calibration
The sensor characteristics slowly shift over time and cause the sensor to lose accuracy. The sensor
must be calibrated regularly to maintain accuracy. The calibration frequency varies with the
application and is best determined by experience.
Use air (zero calibration) and a reference solution or process sample to define the calibration curve.
A reference solution calibration is recommended for the best accuracy. When the process sample is
used, the conductivity of the process sample must be identified with a certified secondary verification
instrument.
During calibration, data is not sent to the datalog. Thus, the datalog can have areas where the data is
intermittent.
4.3.2 Calibration limits
A calibration will fail if the value is ± 10% of the target value.
4.3.3 Cell constant
Before a sensor calibration is done, make sure that the sensor cell parameters are correct as follows:
1. Select the main menu icon, then select Devices. A list of all of the available devices shows.
2. Select the sensor and select Device menu > Calibration.
3. Select Cell constant parameters, then push OK.
4. Enter the cell constant value recorded on the test certificate that is supplied with the sensor.
4.3.4 Change calibration options
The user can set a calibration reminder and/or include an operator ID with calibration data from the
Calibration options menu.
1. Select the main menu icon, then select Devices. A list of all of the available devices shows.
2. Select the sensor and select Device menu > Calibration.
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