Hanna Instruments HI 83749 - Manual (Page 10)

10
CUVET
The cuvet is part of the optical system and measurements can be affected by the glass imperfections,
dirt, dust, scratches, or fingerprints present on the cuvet surface.
CUVET HANDLING
• Any cuvet with visible scratches must be discarded.
• Always store the cuvets in separate boxes or with separators between them to avoid scratches on
the surface.
• Whenever a cuvet is placed into the instrument, it must be dry outside, free of fingerprints or
dirt. Wipe it thoroughly with HI 731318 (tissue for wiping cuvets, see Accessories Section,
page 39) or a lint-free cloth prior to insertion.
CUVET OILING
• For low turbidity readings (<1.0 NTU) the cuvets should be oiled outside with the supplied
HI 93703-58 Silicone Oil. Use only one single drop of oil and then wipe the cuvet thoroughly
with a lint-free cloth.
SAMPLING TECHNIQUE
When you make turbidity measurements it is important to take a representative sample.
• Gently mix the sample before filling the cuvet.
• Samples should be analyzed immediately after collection because turbidity can settle or change in
time.
• Pay attention when working with cold samples that no condense is formed on the outside of the
cuvet. We recommend to work always with samples at room temperature.
The instructions listed below should be carefully followed to ensure best accuracy.
GENERAL TIPS
• Always cap the cuvets to avoid spillage of the sample into the instrument.
• Always close the lid of the instrument during measurement.
• Keep the lid of the instrument closed when it is not used to prevent dust or dirt entering.
• Put always the instrument on a flat, rugged surface when taking measurements.
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
31
SET EPA COMPLIANCE MODE
When EPA compliance reading is on, “EPA” message
is displayed on the secondary LCD and the reported
values are rounded to meet EPA reporting
requirements.
• To edit the EPA mode, press CAL/RCL when EPA
compliance reading panel is displayed.
The parameter setting and “CFM” tag will start
blinking.
• Press the UP or DOWN keys to set the EPA
compliance mode on or off.
• Press LOG/CFM to save the setting. The new
selected option of the parameter will be
displayed on the LCD.
Alternatively, press CAL to exit without saving
the new settings.
SET BEEPER
The HI 83749 has a built-in beeper that signals
the tag read, the key press and the error conditions.
The beeper can be selected to be on or off.
• To set the beeper on or off, press CAL/RCL when
set beeper panel is displayed.
The beeper status and the CFM tag will start
blinking.
• Press the UP or DOWN keys to set the beeper on
or off.
• Press LOG/CFM to save the change. The new
selected option will be displayed on the LCD.
Alternatively, press CAL to exit without saving
the changes.
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