Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 139)

<11. CALIBRATION OF ISC (Inductive Conductivity)>
11-4
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
NOTE
The temperature compensation should be set to NaCl when confirming zero during air
calibration.
NOTE
The temperature compensation is not performed around zero. In this case, a warning may be
issued.
Not being wet, the sensor measures the conductivity of air, which is close to zero. Because
zero conductivity is out of the range for temperature compensation (this range is based on the
temperature and conductivity of solutions and is preset to 0.033 μS/cm at 20°C), a warning may
be issued. This is not a device error.
The conductivity of air is zero and it does not have a temperature coefficient. Execute zero
calibration regardless of the warning.
11.4 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.
11.5 Temperature coefficient
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 coefficient 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.” (Refer to section 10.1.4)