English (GB)
20
3. Start the calibration by pressing [OK].
– The sensor data are then read in by an
automatic read function and the calibration is
carried out.
– The gradient (sensitivity) of the sensor is
calculated.
4. The calibration result is displayed automatically
directly following the calibration:
– The sensor gradient is output in µA/ppm.
Calibration result
• The result of the current (last) calibration can be
displayed in the code menu at any time:
– Code 51: display of calibrated gradient in
µA/ppm.
Error message when reading in the current signal
of the sensor system
• The alarm LED flashes.
• The coded display output flashes.
*13*: Gradient error
The alarm is output if the plausibility check
establishes the following:
Upward/downward violation of the following gradient
ranges depending on the selected measuring cell:
• Press [OK] to acknowledge the error message
and return to the display level.
• The calibration data are then imported.
9.6.6 Calibration of the pH value; Conex
®
DIS-PR
Enter buffer solution temperature
The temperature of the buffer solution must be
entered in the code menu prior to the calibration.
1. Select code menu 44, and press [OK] to confirm.
2. Enter the buffer temperature in °C using the [Up]
or [Down] button and press [OK] to confirm.
3. Leave the code menu using Exit, and return to
the display level.
See section 9.6.4 Temperature compensation;
Conex
®
DIS-PR.
Select buffer values, read in buffer values and
calibrate
1. Press [Cal] and select the calibration menu. The
Cal LED next to the [Cal] button illuminates.
– To prevent overdosing, the controllers are
switched off and the actuators closed.
– A two-point pH calibration is used.
– The buffer value pH 4.01 appears
automatically.
2. Modify the buffer value if required using the [Up]
or [Down] button.
3. Fill buffer solution 1 from the supply bottle into a
clean vessel.
4. Immerse the combination electrode into the
buffer solution.
5. Start the automatic read function AUTO READ
(reading in of measured signal) and the
calibration by pressing [OK]. The buffer value is
displayed flashing.
During the pH calibration, the automatic read
function AUTO READ ensures that the correct
electrode signal is only read in for the buffer
value if the measured signal remains stable for a
defined period of time.
6. Discard the first buffer solution
– Do not return it to the supply bottle!
– Flush the combination electrode with water.
– The buffer value pH 7.00 appears automatically
once the first buffer value has been read in.
7. Modify the buffer value if required using the [Up]
or [Down] button.
8. Fill buffer solution 2 from the supply bottle into a
clean vessel.
9. Immerse the combination electrode into the
second buffer solution.
10. Start the automatic read function and the
calibration by pressing [OK]. The buffer value is
displayed flashing.
• Discard the buffer solution and flush the
combination electrode with water. The calibration
result is automatically displayed directly after the
calibration: Sensor gradient in mV/pH.
11. The following display is shown by pressing [OK]:
Asymmetry potential of combination electrode in
mV.
12. Return to the display level by pressing [OK].
Measuring cell Lower limit Upper limit
AQC-D1/-D11 7.0 µA/ppm 70.0 µA/ppm
AQC-D2/-D12 2.5 µA/ppm 70.0 µA/ppm
AQC-D3/-D13 2.5 µA/ppm 70.0 µA/ppm
The instrument is operating in emergency
mode! Remedy the fault, see section
11. Fault finding, and calibrate again!
The calibration value is saved even during
power off (failure). To check the current
calibration value use code 51.