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It is recommended to calibrate the instrument frequently, especially if high accuracy is required.
The EC range should be recalibrated:
• Whenever the EC electrode is replaced.
• At least once a week.
• Before USP measurement.
• After testing aggressive chemicals.
• When calibration alarm time out is expired - “
CAL DUE
” blinks (if feature is enabled in
SETUP
).
• If
“Outside Cal Range”
message blinks during EC measurement (the measurement range is not
covered by current calibration, if feature is enabled in
SETUP
).
Note: TDS and Resistivity readings are automatically derived from the EC reading and no specific
calibration is needed.
PROCEDURE
HI98197
instrument offers a choice of 7 memorized standards (0.00
µ
S/cm, 84.0
µ
S/cm,
1.413 mS/cm, 5.00 mS/cm, 12.88 mS/cm, 80.0 mS/cm and 111.8 mS/cm).
For accurate EC measurements, it is recommended to perform a calibration in maximum allowed points.
However, at least a two point calibration is suggested (offset calibration in 0.00
µ
S and one in any
other calibration standard).
The instrument will automatically recognize the standards and skip the standard used during calibration.
• If a five point calibration is performed, one of the points must be 0.0
µ
S (offset).
• Pour small quantities of selected standard solutions into clean beakers. For accurate calibration
use two beakers for each standard solution, the first one for rinsing the electrode and the second
one for calibration.
• Remove the protective cap and rinse the electrode with some of the standard solution to be used
for the first calibration point.
FIVE POINT CALIBRATION
• It is recommended to perform the first point calibration as offset calibration.
•
Tap the probe repeatedly to remove any air bubbles that may be trapped inside the sleeve.
• For offset (zero) calibration, just leave the dry probe in the air.
• From EC range press
CAL
to enter calibration screen.
• Leave the probe in the air and press
EC
. The instrument will display the measured EC on the LCD,
first expected standard and the temperature reading.
EC CALIBRA
TION
