Pr
o
Minent
®
Page 133
pH/Chlorine Dioxide
Calibration of the Chlorine Dioxide Sensor
The calibration (slope calibration) of the chlorine sensor uses the DPD method. When starting
calibration, the frozen measuring value is proposed; this value may be adjusted to the measured
DPD value using the Up and Down buttons. A calibration will only be possible if the DPD value is
≥
2% of the measuring range. During calibration, control function and metering are maintained.
After successful calibration, all fault determinations relating to the measuring value are started
again.
With a measuring range adjusted to 0 - 0.5 ppm, the zero point may be calibrated in the entire
operating menu in addition to the slope. The zero point calibration should be performed under
realistic conditions with chlorine dioxide-free water. In this case, control will be stopped and
metering will be reduced to the set base load. The 0/4...20 mA output (measured value) is frozen
at the start of the calibration.
IMPORTANT
The measuring range of the chlorine dioxide sensor must correspond to the adjusted
measuring range of the DULCOMETER
®
D2C (factory setting 0 - 2.00 ppm). A possible
alteration of the measuring range must be done prior to calibration. If the measuring range
is altered, all settings are reset to the factory settings.
Possible
values
Initial value
Increment
Lower value
Upper value
Remarks
Buffer
pH 7
0.01 pH
-2 pH
16 pH
Error messages
values pH
4
when both
buffers too close
(<2 pH-values)
Temperature Measured
0.1 °C
0 °C
100.0 °C
value
Error message
Condition
Remarks
During calibration procedure:
Buffer distance too small
Δ
Buffer <2 pH
Recalibrate buffer 2!
Return to permanent display:
pH zero point low
< -60 mV
Basic metering load
Warning, old zero
point and slope
retained
pH zero point high
< +60 mV
„
„
pH slope low
< 45 mV/pH
„
„
pH slope high
> 65 mV/pH
„
„
Measured value pH
„
unsteady
Temperature measured
Warning, old zero
value unsteady
point and slope
retained
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24.02.2009 11:56:12 Uhr
24.02.2009 11:56:12 Uhr
