Hach-Lange POLYMETRON 9240 Operator Manual - Manual (Page 101)

99
Calibration
8.5 Automatic calibration setup
Select the AUTO. CAL. SETUP option to access its
sub-menu and set the calibration parameters.
This allows the analyzer to be automatically calibrated at
pre-defined and regular intervals.
The process is the same as described in Calibrate known
addition on page 94 except it is initiated automatically at the
pre-defined time.
Turn the automatic calibration on or off by selecting Yes or No
as appropriate.
Note that even if this is set to Yes, it is still possible to
calibrate the analyzer manually if required.
CAL.SOL defines the concentration of the calibration solution.
Refer to Calibration solution concentrations on page 93 for
information regarding the concentration of the calibration
solution.
MODE can either be set up to a fixed date or to a specified
Frequency .
If the mode is set to fixed date, enter the day(s) of the WEEK
when the calibration will be performed. Set the day to an
asterisk to skip that day.
Set the HOUR field (HH:MM:SS format on a 24 hour clock) to
the time the automatic calibration should start.
In the illustration left, a calibration is set to start on a fixed
time scale and will begin every Monday, Wednesday and
Friday at 19:30 in the evening.
If the mode is set to frequency, then the week and hour data
fields will be replaced by a TIME PERIOD field. Enter the
calibration frequency in hours into this field.
Finally, in the CALIB ON field, select the channel to be used
for calibration. The number of channels available will depend
on the number of channels configured for the instrument. The
sample concentration being measured on this channel must
be less than 1 per thousand of the calibration solution
concentration, otherwise an error is signalled during
calibration.