Hach-Lange POLYMETRON 9240 Basic User Manual - Manual (Page 18)

Sample channels
Select the SAMPLE CHANNELS option to set up the channel parameters.
Number of channels
1. If the number of channels parameter is changed, an activation key will be required before the
additional channel is recognized.
Channel activation
Using the Up and Down Arrow keys, define whether the channel is active (Activ) or inactive
(Inactiv).
Sequence
The sequence defines the channel order in which samples are measured.
1. Only configured channels can be used in the sequence. For example for a 3-channel analyzer
only values 1,2 and 3 are available.
2. Up to 12 sequences can be defined. If a channel has been deactivated, but is still in the
sequence, it is simply ignored and the next channel in sequence is measured.
3. If there is no sample on a programmed channel, the analyzer will detect this and after 3 minutes
move on to the next channel in sequence. The channel on which the sample is missing will be
assigned the alarm sample x flow < min (where sample x is the name of the channel).
4. If the analyzer is stopped manually from the keyboard, it restarts from the same place in the
sequence.
5. In the event of a power failure, when restarted the analyzer with start at the beginning of the
sequence.
Channel names
Define the name of the channel with free-format alphanumeric text up to a maximum of 8 characters.
CALIBRATION
The instrument cannot be calibrated until at least one complete measurement cycle has been
successfully performed. An attempt to calibrate the instrument before this will result in a “Not
authorized” message being displayed.
In order to obtain accurate measurement results, the analyzer should be calibrated on a regular
basis. Two basic methods of calibration are available:
• Manual calibration - The user can manually perform a calibration on an ad-hoc basis.
• Automatic calibration - Parameters can be set up so that the analyzer will perform a calibration
automatically on pre-defined days at a pre-defined time (see Automatic calibration setup
on page 20). This type of calibration is always done using known calibration solution
concentrations.
Note: Before starting a calibration It is very important to ensure that the Reactivation Frequency parameter (see
Reactivation frequency on page 15) is greater than zero. If set to zero, the electrode reactivation process will not
take place during calibration and as such the measurement results may well be out of limits.
Calibration solution concentrations
N O T I C E
The maximum concentration value for any calibration solution cannot be greater than 2000 ppm. Any value
superior to this is outside the analyzer specifications and cannot be processed.
Manual calibration
For a manual calibration, the calibration solutions must be between 100 ppb and 2000 ppm and
must respect the following rules:
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