Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 147)

<12. OPERATION OF DO (Dissolved Oxygen)>
12-7
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
n Zero Current
= The offset value of a calibrated sensor. This is the offset of the sensor and sensor circuit in the
zero oxygen condition.
n Slope
This parameter indicates the sensitivity of the sensor after calibration. It is indicated as a
percentage of the reference sensitivity based on the selection of the sensor or that has been
entered.
n Sensor Current
= The raw output of the sensor before it is calibrated and temperature compensated.
n Available KOH
This parameter indicates the amount of available KOH remaining in the sensor. This amount
is calculated and displayed by totalizing the amount of KOH consumed by dissolved oxygen
measurements.
When replacing the solution in the sensor, calibration should be made to reset (clear) diagnostic
sensor data.
n Compensation
For compensation of measured value, salinity compensation and pressure compensation are
available. To use pressure compensation, enter the pressure level directly.
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 13.2.7.
The “Reset wellness data” button can reset wellness data.
When a sensor or a membrane 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 figure 12.7.)
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.
DO
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