User Manual

<8. CALIBRATION OF SC (Conductivity)>

8-3

IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00

8.4 Sample

With the sensor in situ, a sample can be taken for laboratory analysis. Sample calibration records

the time and reading, and holds these in memory until the analysis has been completed. The

laboratory data can then be entered regardless of the current process value, without the need for

calculations.

When sample calibration is made with temperature compensation activated, the types of

temperaturecompensationforlaboratoryanalysisequipmentshouldbematched.Useofa

differenttypeoftemperaturecompensationbetweenequipmentcausesanerror.Thestandard

conductivity meter to be used should always be based on the accurate and same temperature

compensation calculation method. Yokogawa recommends that the Model SC82 pocket

conductivity meter be used for this purpose.

Press[TakeSample]torecordacollectedsamplevalueinmemory.Re-entertheSampleCal.

screenandpress[Startcalibration]toperformasamplecalibration.Thisupdatestherecorded

data.

8.5 Temperaturecoefcient

Simply input the solution conductivity at the reference temperature (TR) after allowing the sensor

tostabilizeatelevatedtemperatures.TheFLXA21willcalculatethetemperaturecoefcientfor

you. The ideal temperature for this calibration is the normal process value (TP).

This calibration is enabled if the Temperature Compensation is set to “TC.” (Section 7.1.4)

8.6 Temperature calibration

In order to make the most accurate measurements, it is important to have a precise temperature

measurement. This affects the display of temperature, and the output signal (when used). More

important, however, is the temperature compensation, and calibration accuracy.

The temperature of the sensor system should be measured independently with a high precision

thermometer. The value of “Measured temperature” should then be adjusted to agree with the

reading (zero offset calibration only).

For best accuracy, this should be done as near to the normal operating temperature as possible.