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Operational Guide

Calibration

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 (HI 11311 and HI 12301 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 buer calibration.

For accurate measurements, at least a two-point calibration is recommended.

However, a single point calibration can also be used.

The calibration buers can be selected from the calibration buer list that

includes the standard buers, 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 buer solution and

stir gently. Press CAL. The “CAL” tag will appear and the “7.01” buer will be

displayed on the third LCD line. If necessary, press the

ARROW keys to select a dierent buer value.

The “ ” along with “STIR” tag will be displayed and

“WAIT” will blink on the LCD until the reading is stable.

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Hanna Instruments Edge HI 2020 User Manual

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