12
Conductivity/TDS calibration
This meter is capable of up to 5-point conductivity or TDS
calibration at one point per range:
If you are measuring values in more than one range, make
sure to calibrate each of the ranges you are measuring. All
new calibration data will over-ride existing stored calibration
data for each measuring range you calibrate.
• If you are measuring in ranges near to or greater than
20 mS (10 ppt), or near to or lower than 100 µS (50 ppm),
calibrate the meter at least once a week to get specified
±1% F.S. accuracy.
• If you are measuring in the mid ranges and you washed
the probe in deionized water and stored it dry, calibrate the
meter at least once a month.
• If you take measurements at extreme temperatures, cali-
brate the meter at least once a week.
Preparing for conductivity/TDS calibration
For best results, select a standard value close to the sample
value you are measuring. Alternatively, use a calibration solu-
tion value that is approximately 2⁄3 the full scale value of
the measurement range you plan to use. For example, in the
0 to 1999 µS conductivity range, a 1413 µS solution is a
good solution for calibration.
See the table at left for recommended calibration solution
ranges.
Temperature coefficient:
These meters are factory set to
a temperature coefficient of 2.1% per °C. For most applica-
tions this will provide good results. See Program P8.1 on
page 36 to set the temperature coefficient to a different
value.
See Appendix 2, “Calculating Temperature Coefficients” on
page 45 to determine the appropriate temperature coeffi-
cient for your solution.
Normalization temperature:
The factory default value for
normalization temperature is 25°C. If you need to normalize
to a value other than 25°C, see Program P8.2 on page 36.
TDS conversion factor:
The factory default setting for the
TDS conversion factor is 0.5. If your solution has a different
TDS factor, you can improve calibration accuracy by setting
the TDS factor prior to calibration. See Program P7.4 on
page 35.
See Appendix 1, “Conductivity to TDS conversion Factors”
on page 44 to determine your solution’s TDS factor.
Conductivity /
Recommended
TDS Range
Calibration
Solution Range
Conductivity
0.00-19.99 µS
6.00 to 17.00 µS
0.0-199.9 µS
60.0 to 170.0 µS
0-1999 µS
600 to 1700 µS
0.00-19.99 mS
6.00 to 17.00 mS
0.0-199.9 mS
60.0 to 170.0 mS
TDS
0.00-9.99 ppm
3.00 to 8.50 ppm
10.0-99.9 ppm
30.0 to 85.0 ppm
100-999 ppm
300 to 850 ppm
1.00-9.99 ppt
3.00 to 8.50 ppt
10.0-200 ppt
30.0 to 170 ppt
Conductivity:
0.00-19.99 µS
0.0-199.9 µS
0-1999 µS
0.00-19.99 mS
0.0-199.9 mS
TDS:
0.00-9.99 ppm
10.0-99.9 ppm
100-999 ppm
1.00-9.99 ppt
10.0-199.9 ppt
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