Hach ORBISPHERE3650 Manuel D'utilisation De Base page 16

3. Press CAL again within a 3 second period.
4. The percentage of the measured current to the ideal one is displayed.
5. When the reading is stable, press CAL again.
If the new calibration current is within 25% to 175% of the ideal current, the instrument displays
CAL and returns to the measurement mode. Calibration is now complete, the sensor is
calibrated, and you can proceed with your measurements. If the new calibration current is not
within this range, the instrument displays Err and returns to measurement mode. The system will
not calibrate, and it is likely that a sensor service will be required.
Calibration in line
The in line calibration procedure can be used to calibrate the sensor directly in line, against a liquid
sample with a known dissolved oxygen concentration. To perform this type of calibration, the
instrument must be set for calibration In line. Switch on the instrument, if necessary, and wait a
minute or so for the displayed measurement to settle. Expose the sensor to a liquid sample with a
known gas concentration.
1. Press the CAL button. Remember, this button may have been locked out to prevent an accidental
reset (see Locking out the instrument's CAL button
2. A brief clearing [- - -] message appears.
3. Press CAL again within a 3 second period.
4. A measurement will flash on the LCD, showing the oxygen concentration of the calibration
sample.
5. Assuming you know the gas content to be a certain value, you can adjust the displayed value with
the Up/Down Arrow keys.
6. When the reading is adjusted to the known concentration, press CAL again.
7. The instrument displays CAL and returns to the measurement mode.
Calibration in air
The sensor can be accurately calibrated in air. To perform this type of calibration, the instrument
must be set for calibration In air.
In order to calibrate the sensor in air, you will need to extract it from its mounting or flow chamber,
and wipe dry the sensor protection grille (if applicable).
Calibration is best achieved using the storage cap that protected the sensor during shipment. Put
several drops of tap water in the cap, shake out the excess, and then attach it to the sensor by
means of its collar. It is best to leave the cap slightly loose, to avoid compressing the air inside. The
cap and sensor should be about the same temperature.
Switch on the instrument, if necessary, and wait a minute or so for the displayed measurement to
settle.
1. Press the CAL button. Remember, this button may have been locked out to prevent an accidental
reset (see Locking out the instrument's CAL button
2. A brief clearing [- - -] message appears.
3. Press CAL again within a 3 second period.
4. The percentage of the measured current to the ideal one is displayed.
5. When the reading is stable, press CAL again.
If the new calibration current is within 25% to 175% of the ideal current, the instrument displays
CAL and returns to the measurement mode. Calibration is now complete, the sensor is
calibrated, and you can proceed with your measurements. If the new calibration current is not
within this range, the instrument displays Err and returns to measurement mode. The system will
not calibrate, and it is likely that a sensor service will be required.
16 English
on page 14 for details).
on page 14 for details).