Operating instructions

Aztec ADS430 | Optical dissolved oxygen probe | OI/ADS430–EN Rev. A 11

6 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 OI/AWT440-EN for all transmitter menu options.

6.1 Calibrate menu

IMPORTANT (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 Section 6.1

below.

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).

Calibrate

Exit

Select

Menu Comment Default

S1(to 4) :RDO 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

2SO3).

Hold Outputs Enable / disable the Hold Outputs function. If enabled, the current

outputs and alarm functions are held during calibrations.

Enabled