JBL ProFlora pH Control Touch Mode D'emploi page 42

Miscellaneous
Calibration
Display during waiting time: Whilst the sensor is in the bu er solutions the device measures
the sensor voltage delivered and waits until the signal has stabilised. This takes a maximum
of 1.5 minutes per bu er solution.
The following appears on the display during the waiting time:
First line: pH value of the required bu er and voltage in millivolt
Second line: temperature in °C
Third line: progress bar
At the far right of the display is shown the current accuracy of the measurements, newly
calculated for the particular sensor for each calibration. Example: +/- 0.02 pH. The higher this
value is, the worse the condition of the sensor is.
Calibration reminder: the device has an automatic calibration reminder function which gives
a reminder of calibration every 30, 45 or 60 days. The time to the next calibration is displayed
in days and hours in the value overview (chapter 4).
5 days before expiry of the calibration deadline the remaining time appears top right on idle
screen. Its colour changes to red two days before calibration. After the expiry of the deadline
the display ashes and counts the days with a minus sign, to remind of the overdue days for
the calibration.
If calibration cannot be carried out at that moment, the device continues to measure and
control as before. However, the warning signal ( ashing) can only be cancelled by calibration.
The time to the next calibration can only be recorded as long as the device is connected to
the power supply. After a longer pause, it is vital that calibration is carried out before the
device is used again to measure and regulate.
Error messages during or after the calibration:
The measuring capability of pH sensors changes with age i.e. it begins to deviate from
the original setting. Regular re-calibration (comparison of the device with the changed
measuring ability of the sensors) is vital to obtain reliable results. As a rule, the more often,
the better.
If the message "Sensor defect" with the symbol of the operating instructions appears at the
end of the calibration process together with an error message such as DELTAV, OFFSET or
similar, calibration should be repeated.
In the event that calibration is unsuccessful a second time, consult the following table.
Error message
DELTAV
38
Cause
Voltage di erence per full pH unit
is less than 35 mV: sensor too old
or accidentally calibrated twice
with same bu er solution.
Remedy
Repeat calibration, check
correct bu er solution is used. If
unsuccessful, connect new sensor
and calibrate.