Aqualytic AL400T-WL, Instruction Manual, Page: 18 / 32

18 AL400T-WL_2a 07/2011
2.3.2 User calibration
2.3.2.1 When to calibrate?
The turbidimeter was calibrated at the factory and does not require user calibration before
use.
Therefore, it is possible to use the instrument directly out of the box. However, re-calibration
of the instrument is recommended to help with familiarization and the operation of the in-
strument and the calibration procedures. In addition, re-calibration is recommended at least
once every three months.
The instrument requires three standards to be fully calibrated.
During calibration, the instrument performs several system self-diagnostics. As such, several
warning messages may be displayed. If the instrument detects an irregularity (detectors
or lamp) a warning message will be displayed. If this occurs please contact an authorised
technical services department.
2.3.2.2 Calibration Procedure
The following procedure is recommended to perform a full range calibration. Ensure that the
calibration standards have been indexed prior to proceeding.
1. Select the calibration function of the instrument by
pressing the
CAL
button once. The
“CAL”
icon will be il-
luminated on the display with “1000” flashing indicating
the standard required for this step of the calibration.
2. Insert the 1000 NTU standard into the sample chamber
and press down until the cuvette snaps fully into the
instrument. Align the indexing ring with the arrow on
the instrument (see section 2.3.3.4 if the standard is not
already indexed).
3. Press and hold the [ ] key while making fine adjustments
to the indexing. Release the button to initiate the cali-
bration. The display will now show a 30 second count-
down.
4. When the instrument has completed the calibration on
the 1000 NTU standard, it will briefly display 1000 to
indicate that it was calibrated and then prompts for the
10 NTU standard with a flashing
“10.0” .
1000
NTU
FNU
CAL
10.0
NTU
FNU
CAL
30
NTU
FNU
CAL