Conductivity Test Notes - eXact pH+ Instruction Manual

16

CONDUCTIVITY TEST NOTES

• The TDS and Salinity measurements are calculated from the
conductivity measurements by using conversion factors.
• The meter can recognize 84μS, 1413 μS/cm and 12.88 mS/cm
conductivity calibration solutions. The user can conduct 1 to 3 points
calibration. Refer to the table below. Usually calibrating the tester with
1413 μS/cm conductivity buffer solution alone shall meet the testing
requirement. However, we recommend choosing a calibration solution
close to the expected conductivity of your sample.
Calibration indication
Icon
• The tester has been calibrated before leaving the factory. For best
accuracy we recommend testing a conductivity buffer solution
before use. If the error is large, then calibration is needed.
• To maintain the accuracy of conductivity calibration solutions, we
recommend replacing the solutions after 3 to 5 uses. To prevent
contamination, Do NOT pour used calibration solutions back into
the original bottles.
• Temperature compensation factor: The default setting of the
temperature compensation factor is 2.0%/°C. Users can adjust the
factor depending on the solution or experimental data (see table
below). Use parameter setting P4 to adjust the factor.
Solution
NaCl
5% NaOH
Dilute ammonia
10% Hydrochloric acid
5% Sulfuric acid
• 1000 ppm = 1 ppt
• TDS and conductivity are linearly related; the conversion factor
ranges from 0.40-1.00. The factory default setting is 0.71. Salinity
and conductivity are also linearly related; the conversion factor
is 0.5. The tester only needs to be calibrated in Conductivity
mode. After calibration for conductivity, the meter can switch from
conductivity to TDS or salinity.
• Conversion Example: if conductivity measurement is 1000μS/
cm, then the default TDS measurement will be 710 ppm (under the
default 0.71 conversion factor), and the salinity will be 0.5 ppt.
• Avoid cross-contaminating the conductivity standard solutions.
Rinse the sensors and blot dry after every measurement.
©2018, Industrial Test Systems, Inc. Printed in USA
Calibration
Standards
84μS/cm
1413 μS/cm
12.88 mS/cm
compensation factor
1000 μS = 1 mS
Measuring Range
0 - 200 μS/cm
200 - 1999 μS/cm
2 - 20 mS/cm
Temperature
2.12%/°C
1.72%/°C
1.88%/°C
1.32%/°C
0.96%/°C