Installation Instructions

Calibration Page 17/24

Installation and commissioning instructions

VII. Calibration

CAA320X et CAA330X probes require a calibration of the slope of the sensor and, if necessary (low

chlorine measurement), a calibration of the zero point. Depending on the physio-chemical parameters

of the water, the gain multiplier switch can be used.

1) Calibration of the sensor slope

A calibration of the slope of the sensor is required after the first commissioning (about 3h) and on a

regular basis for normal chlorination operation. If chlorine dioxide is present, the calibration shall take

account of its presence. The action of chlorine dioxide is 6 times greater than the measured chlorine.

 Circulate chlorinated water in the chamber, wait for stabilization of the reading on the

control device.

 The chlorine value must be at least 10% of the measurement scale.

 Perform a chlorine measurement using a reference device.

 Perform a countermeasure to validate this standard value.

 Enter this value in the regulator to validate calibration.

In order to perform a correct calibration, the probe must be used in the measuring chamber,

at nominal pressure with the recommended flow rate (see specifications).

2) Zero-point calibration (if required)

Zero-point calibration is required when measuring at low chlorine value. In principle, the cell has a very

stable “zero” in absence of chlorine or any other oxidant. However, in order to ensure a perfect zero

integrating the drifts of the measuring chain, it should be verified and, if necessary, calibrated.

 Clear the calibrations on the analyzer.

 Turn off water circulation in the chamber.

 Allow values to stabilize for several minutes.

 Once the stability of the measure is perfect, make the zero on the analyser

 Reopen the circulation of water

 After the zero-point calibration a calibration of the slope of the probe should be done (See

§ above)

3) Use of the gain multiplier switch

Depending on the pysico-chemical parameters of the water, the gain multiplier switch can

be used. This switch allows to multiply the gain of the slope by 5.

Example 1 :

The use of stabilizer will cause a drop in chlorine measurement. If necessary, use

the gain multiplier switch by passing it in position X5.

Example 2 :

In high pH seawater the measurement of chlorine or brome will be low. If

necessary, use the gain multiplier switch by passing it in position X5.