Hach 2100AN IS, User Manual

Page: 31 / 52

7. After the sample
flow stops and the
display stabilizes, read
and record the value.
Note: To print or send
(via RS232) a
measurement record,
push PRINT.
Measurement techniques
Measurements may be made with different operation mode settings and
optional accessories.
Calibrate the instrument whenever the sample cell pathlength is
changed.
Manual or automatic ranging
The manufacturer recommends that ranging be set to automatic for most
measurements.
The setting can be changed at any time during sample measurement.
Push
RANGE repeatedly to step the instrument from automatic ranging
to manual ranging and then scroll through the manual range settings.
"MANUAL" is shown above the Range Mode label on the instrument
when manual ranging is selected. "AUTO" is shown below the Range
Mode label on the instrument when automatic ranging is selected.
Notes:
• When manual ranging is selected, the display flashes all 9s when the
sample being measured is greater than the selected range. The
display flashes all 0s when the sample measured is less than the
selected range.
• When automatic ranging is selected, the display flashes 9s when the
sample is greater than the maximum range of the instrument. The
display flashes 9s when Ratio is off and the measurement is greater
than 40 NTUs (1000 FNUs or 9.8 EBCs). Turn Ratio on to increase
the range. Refer to
Measure over-range samples on page 24.
• When automatic ranging is selected, the display flashes all 0s when
the measurement is less than the range of the instrument (i.e., less
than 20 FAU) or a negative value. Calibrate the instrument. When
measuring absorbance or transmittance, set the zero reference point
again.
Signal averaging on or off
Signal averaging corrects for reading fluctuations that are caused by
random drifting particles in the sample. When signal averaging is on, an
average reading is calculated every 3 seconds and shown on the
display.
The manufacturer recommends that signal averaging be on for most
measurements.
English 29