6
A DS 4 20
| D I SS O LV ED OX YG EN P R O B E | O I/A DS 4 2 0 - EN R E V. A
3 Calibration
This section describes how to calibrate the probe and involves measuring the probe’s sensitivity to oxygen by exposing the probe
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
for all transmitter menu options.
Note .
• Do not perform a calibration until the probe and transmitter are installed and ready for operation.
• Before removing the probe for calibration purposes, set the currents outputs and alarms to Hold (enabled via the Operator
Menu/Manual Hold function).
• After calibration and probe replacement, reset the currents outputs and alarms – see
below.
Calibrate menu
Calibrate
Menu
Exit
Select
Used to calibrate the probe.
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).
Menu
Comment
Default
S1 (to 4) :DO
Select the optical dissolved oxygen probe to calibrate.
Probe Calibration
Calibration Type
1-Point Cal
Select to perform a 1-point calibration in water-saturated air (100% saturation):
2-Point Cal
Select to perform a 100 % saturation calibration in water-saturated air and a 0 %
saturation calibration in an oxygen-depleted solution, e.g. sodium sulphite
(Na
2
SO
3
).
Hold Outputs
Enable/disable the
Hold Outputs
function. If enabled, the current outputs and
alarm functions are held during calibrations.
Enabled
