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4 Calibration
This section describes how to calibrate the sensor and involves
measuring the sensor's sensitivity to oxygen by exposing the
sensor to water-saturated air.
Calibrations are initiated via the Cal prompt displayed on
Operator pages or via the Calibrate and Advanced menu
items on the Access Level page – refer to transmitter Operating
instructions
OI/AWT420
for all transmitter menu options.
Note .
• Do not perform a calibration until the sensor and transmitter
are installed and ready for operation.
• Before removing the sensor for calibration purposes, set the
currents outputs and alarms to Hold (enabled via the
Operator Menu/Manual Hold function).
• After calibration and sensor replacement, reset the currents
outputs and alarms – see Calibrate menu below.
Calibrate menu
Menu
Calibrate
Exit
Select
Menu
S1 (to 4) :DO
Probe Calibration
Calibration Type
1-Point Cal
2-Point Cal
Hold Outputs
A D S 4 2 0 | D I S S O LV E D OX YG E N S E N S O R | O I/A D S 4 2 0 - E N R E V. B
Used to calibrate the sensor.
Access to the Calibrate menu is permitted via the Calibrate and Advanced levels only.
Note . During calibration, current outputs and alarms are set to Hold automatically if
Hold Outputs is enabled (see below).
Comment
Select the optical dissolved oxygen sensor to calibrate.
Select to perform a 1-point calibration in water-saturated air (100% saturation):
Select to perform a 100 % saturation calibration in water-saturated air and a 0 % saturation
calibration in an oxygen-depleted solution, e.g. sodium sulfite (Na
Enable/disable the Hold Outputs function. If enabled, the current outputs and alarm functions are
held during calibrations.
SO
).
2
3
7
Default
Enabled
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