Hach LANGE si628 P Bedienungsanleitung Seite 24

4. Operation
4.8. Calibration of redox electrode
The metallic electrodes do not show significant drift of potential, for this reason usually they are not
calibrated. However, some deviations of potential may occur after continued use of the electrode due to al-
terations of the metallic surface or reference system contamination. For the compensation of these deviations,
it is recommended the calibration using redox standard of 220 mV (25 °C).
1. Selection of the temperature of the standard.
2. Calibration with standard 220 mV.
If there is an anomaly during the calibration,
there will be an error message.
Introduce code 100
Introduce the standard's temperature with the keys
Theoretical value of the standard at calibration temperature
Automatic change of the display. It occurs once the reading
is stable
Notes: During Calibration the instrument is in Hold state:
• Limit and cleaning contact relays are opened. (Alarm OFF).
• Current output is frozen at the value programmed in Hold.
To quit the Hold state it is necessary to return to Measure.
The Current output 4 to 20 and the Relays will activate in 10 sec.
For practical reasons, during CALIBRATION, it is recomended
to introduce the buffer temperature manually despite the ATC
probe (Pt 1000) is connected.
When the required adjustment for performing the calibration is
more than 60 mV, there will be the following error message.
20
si628 P_HACH_LANGE_Ed.0510.indd ANG:20 si628 P_HACH_LANGE_Ed.0510.indd ANG:20
M E A S U R I N G
365 mV
CODE 000
CALIBRATION
Insert buffer
220 mV 25°C
CALIBRATING
228 mV 20°C
CALIBRATION OK
MEASURE mV
M E A S U R I N G
354 mV
mV adjust
> 60 mV
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