User Manual

<3. OPERATION OF pH/ORP>
3-8
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
If both impedance measurements are disabled (Error setting: Off), the display shows “- - - - (bar)”.
If either impedance measurement 1 or 2 is enabled, the display shows both the impedance
values.
l Impedance 2
Impedanceshowstheelectricalresistanceofthereferenceelectrodeliquidjunction.Theliquid
junction forms the electrolytic contact between the reference electrode and the measuring
electrode,soitmustbekeptcleanandlledwithconductiveelectrolyte.Otherwisethe
measurement will suffer from instability, drift and measuring errors. The electrical impedance is
one of the most important.
In case of “Input Impedance setting” is “High” and the measured input-2 impedance value is
higherthan100kΩ,thedisplayshows“MΩRANGE”.Themeasuredinput-2impedancevalueis
lowerthan100kΩ,displayshows“BAD”.
If both impedance measurements are disabled (Error setting: Off), the display shows “- - - - (bar)”.
If either impedance measurement 1 or 2 is enabled, the display shows both the impedance
values.
n Sensor wellness
At the Sensor wellness window, the soundness of a module is displayed. A larger number of n
in each gauge indicates that the parameter concerned is sound. A gauge is indicated for only
those parameters whose sensor wellness setting is “enabled,” while a bar (----) is displayed if the
sensor wellness setting is “disabled.”
SensorwellnesssetupcanbemadeinCommissioning→Measurementsetup→Sensordiag.
settings. For details, see section 4.2.7.
The “Reset wellness data” button can reset wellness data.
Whenasensororanelectrodeisexchangedorreplaced,sensorwellnessdatashouldbereset.
NOTE
When a sensor is replaced, the replacement can be recorded manually into a logbook. (Refer to
thegure3.9.)
n Last calibrated
=dateonwhichthelastsensorcalibrationwasperformed.ThedisplayedvalueoftheZeroisthe
result of this calibration. The displayed value of Slope was calibrated on this date only if the last
calibration was a 2-point calibration.
n Calibration due
=thedatewhenthecalibrationmustbedonenextaccordingtothesettingsofthecalibration
interval.ThecalibrationintervalsaresetinCommissioning→Measurementsetup→Calibration
settings→Limitsandtiming.
n Projected maintenance
The projected maintenance function predicts the date when the sensor unit will need recalibrating
for maintaining measurement accuracy. The function checks the input-2 impedance (reference
impedance) every 24 hours.
The function predicts the date when the input-2 impedance will cross the upper or lower limits,
and indicates the date and its status (the status is displayed in parentheses).