Calibration – Hach-Lange PHC745 User Manual
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3. Push down softly to return the sleeve junction to its initial position. Refer to
.
Note: Be careful not to open the sleeve junction too much. If the electrolyte flow is too high, the
probe will empty quickly and will be necessary to fill the electrolyte frequently.
4. To close the sleeve junction, slowly move the sleeve to the glass bulb until electrolyte
flow stops.
Note: Always close the sleeve junction when the probe is not in use.
Make sure to close the sleeve junction and refill the inner electrolyte after use. If all
electrolyte goes out the probe can become dry and permanently damaged.
Figure 3 Sleeve junction
Calibration
Before calibration:
The probe must have the correct service-life time stamp. Set the date and the time in the meter before the probe is attached.
It is not necessary to calibrate again if a calibrated probe is moved from one HQd meter to another. Make sure that the
additional meter is configured to use the same calibration options.
To view the calibration data, push
, then select View Probe Data>View Current Calibration.
If two probes are connected, push the UP or DOWN arrow to change to the single display mode to show the Calibrate option
(available only on HQ40d and HQ440d meters).
Prepare the probe for use (refer to
Calibration notes:
•
Use buffers that are two pH units apart.
•
Select additional standard sets with the minimum number of calibration points in the
Calibration Options. For a two-point calibration, select: one buffer with a pH above
and one buffer with a pH below the sample pH. For a one-point calibration, select the
buffer nearest to the sample pH.
•
The calibration is recorded in the probe and the data log. Send the calibration to a
PC, a printer or a flash memory stick if connected.
•
Air bubbles under the sensor tip can cause a slow response or an error in the
measurement. If there are bubbles under the sensor tip, carefully shake the probe to
remove the bubbles.
•
Make sure that the filling hole is open and above the sample solution level.
•
Use a laboratory stirrer or shake the probe from side to side in the solution to refresh
the reference junction.
•
The meter display shows "Stabilizing" and a progress bar as the probe stabilizes in
the standard. The display shows the buffer and the temperature corrected pH value
when the measurement is stable.
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