Hanna Instruments HI 88713 - Manual (Page 13)

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Note: If necessary, press UP or DOWN key to edit the calibration point value to match the exact value of
the standard as measured with a reference turbidimeter.
• Close the lid and press “Read” functional key. The display will show the value blinking and the
light icon during measurement.
• At the end of the measurement, the calibration
is saved and the display will briefly show “Store...”.
The instrument returns in the main screen.
CALIBRATION ERROR MESSAGES
If the value of the standard read during the calibration is too far from the set value, the instrument
will display a standard low or a standard high message.
Check if the correct standard is used or prepare a fresh standard, if formazine is used, and repeat the
reading of the standard.
If the calculated calibration coefficients are outside a
certain range a calibration error message is displayed.
FOUR-POINT CALIBRATION
•
Remove the third standard cuvette.
• Place the cuvette for third calibration point:
• 750 FNU (NTU) calibration cuvette for NTU
ratio mode.
• 750 NTU formazin prepared standard for NTU
non-ratio and FNU modes.
• 2000 NTU formazin prepared standard for FAU
mode.
Note: If necessary, press UP or DOWN key to edit each calibration point value to match the exact value
of the standard as measured with a reference turbidimeter.
• Close the lid and press “Read” functional key. The display will show the value blinking and the
light icon during measurement.
• The “Store...” message is displayed for FAU, FNU and NTU non-ratio modes and the calibration
is saved. The instrument returns to the main screen.
• The fifth proposed calibration point, 2000 NTU for NTU Ratio mode, is displayed.
• At this moment it is possible to exit calibration by pressing “End” functional key.
• If the calibration is terminated, the display will
briefly show “Store...” and the four point calibration
is saved. The instrument returns in the main screen.
FIFTH CALIBRATION POINT (NTU Ratio Turbidity only)
• Remove the fourth standard cuvette.
• Place the 2000 NTU calibration cuvette (or the
fifth prepared formazin standard) into the holder,
with the cuvette mark aligned to the sign on the
instrument top.
O UT CAL RANGE FUNCTION
The instrument has a mechanism to prevent taking
measurements in a range where the calibration
does not assure the best results. The message
“Out of Calibration Range” is displayed on the
message line in the following situations:
• When the first calibration point is over 0.15 FNU and the reading is under 10 FNU.
• When two point calibration was performed and the reading value is over 40 FNU.
• When a three point calibration was performed and the reading is over 150% of the the third point value.
• When a four point calibration was performed and the reading is over 200% of the the fourth point value.