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30
If the instrument is not calibrated the calibration history has been deleted, or it has been calibrated
only at one point, the electrode condition and the electrode response gauges will be empty.
For a continuous display of the electrode’s condition and response, daily calibration is necessary. This
information can also be viewed in the GLP data.
Junction Condition (HI11311 and HI12301 Only)
edge’s pH Sensor Check™ feature assess the health of the pH electrode’s reference junction during
each calibration. The junction gauge may be viewed directly in GLP but will also blink a warning on
the display if the junction is compromised (not 100%). Should this happen, the junction condition
will appear on the display with the junction blinking. The Junction Condition is a function of the
electrode’s reference impedance which should be kept low. If the reference junction becomes fouled
from a precipitate or coating, the impedance will rise and cause the pH measurement to drift. This
diagnostic feature serves as a warning to clean the sensor.
Calibration in Basic Mode
Procedure
Basic mode operation permits up to three‑point buffer calibration.
For accurate measurements, at least a two‑point calibration is recommended. However, a single
point calibration can also be used.
The calibration buffers can be selected from the calibration buffer list that includes the standard
buffers, pH 4.01, 6.86, 7.01, 9.18 and 10.01.
Three-Point Calibration
Submerse the pH electrode approximately 3 cm (1¼”) into a buffer
solution and stir gently. Press
CAL/MODIFY
key. The “CAL” tag will
appear and the “7.01” buffer will be displayed on the third LCD line.
If necessary, press the
keys to select a different buffer value.
OPERA
TIONAL GUIDE
Summary of Contents for HI 2002
Page 1: ...INSTRUCTION MANUAL pH...