Necessity of calibrating the zero point
Calibration of the zero point is not generally necessary.
Calibration of the zero point is only necessary if the
sensor is operated at the lower limit of the measuring
range or if the 0.5 ppm sensor version is used.
During the calibration, the DULCOMETER
®
D1Cb / D1Cc sets the
control outputs to "0". Exception: a basic load or a manual control
value has been set, this remains active. The mA standard signal
outputs are frozen. The measured value frozen at the start of cali‐
bration is suggested as a DPD value. The DPD value can be set
using the arrow keys. Calibration is only possible if the DPD value
is ≥ 2 % of the measuring range of the sensor.
NOTICE!
Prerequisites for correct calibration of the sensor slope
– The DPD method required by the feed chemical
employed will be used
– The run in period for the sensor has been adhered
to
– There is permitted and constant flow at the in-line
probe housing
– There is temperature equalisation between the
sensor and the sample water
– There is a constant pH value in the permitted
range
The sensor is fitted, flushed with sample water and connected
electrically to the DULCOMETER
®
D1Cb / D1Cc and run-in.
There has to be adequate feed chemical in the sample water for
calibration (> 2% of the measuring range of the sensor).
Remove sample water directly at the measuring point and deter‐
mine the content of metering medium in the sample water in "ppm"
using an appropriate reference method (e.g. DPD, titration etc.).
Enter this value as follows at the DULCOMETER
®
D1Cb / D1Cc:
1.
Select Calibration menu. Then press
ð
The current measured value will now be frozen.
2.
Take a sample of water and perform a reference measure‐
ment within 15 minutes
3.
Select "DPD value" of unit to be calibrated using the key
4.
Continue with
5.
If necessary, match the flashing ppm value to the value
determined with the measurement using the keys, , and
ð
The mA value of the sensor shown in this display now
corresponds to the measured value in "ppm".
6.
Then press the following key twice
ð
The display now shows the value determined for the zero
point and slope. Refer to the Error Message table should
an error be displayed.
Calibration of amperometric sensors:
slope (in the reduced and complete
operating menu)
Start up
26
