Hach-Lange 2100 AN IS Laboratory Turbidimeter Basic User Manual - Manual (Page 12)

• In Calibration mode, automatic range and signal averaging on are
selected. When calibration is completed, all operational modes go
back to the last settings.
• All nephelometric (turbidity units of measure) calibrations are done at
the same time.
• Ratio-on and Ratio-off calibration data is measured and recorded at
the same time.
• The 4000-NTU and 7500-NTU standards do not have to be measured
during calibration if FNUs will be measured. Push CAL/Zero after the
1000 NTU standard is measured to complete the calibration
procedure.
• The 7500-NTU standard does not have to be measured during
calibration if turbidity less than 4000 NTU will be measured. Push
CAL/Zero after the 4000 NTU standard is measured to complete the
calibration procedure.
• The FNU values of StablCal standards and formazin standards are
calculated using the conversion factors of 1 FNU = 1 NTU.
StablCal calibration procedure
1. Push CAL/Zero.
The CAL/Zero light
turns on, and the mode
display shows "00". The
NTU value of the
dilution water that was
used in the previous
calibration is shown on
the display. 2. Get the < 0.1 NTU
vial. Clean the vial with
a soft, lint-free cloth to
remove water spots and
fingerprints. Do not
invert the vial. 3. Apply a small bead
of silicone oil from the
top to the bottom of the
vial. 4. Use the oiling cloth
to apply the oil equally
to the surface of the
vial. Remove the
excess oil. Make sure
that the vial is almost
dry. 5. Put the vial in the
sample cell holder with
the triangle on the vial
aligned with the
reference mark on the
sample cell holder.
Close the cover. 6. Push ENTER.
The instrument display
counts down, then
measures the standard.
The next expected
standard (e.g., 20.00) is
shown. The mode
display shows "01".
12 English