IM 12D08N05-01E
APP-7
<APPENDIXES>
Table 3
NaCl values at 25 °C
Weight %
mg NaCl/kg
Conductivity
0.001
10
21.4 µS/cm
0.003
30
64.0 µS/cm
0.005
50
106 µS/cm
0.01
100
210 µS/cm
0.03
300
617 µS/cm
0.05
500
1.03 mS/cm
0.1
1000
1.99 mS/cm
0.3
3000
5.69 mS/cm
0.5
5000
9.48 mS/cm
1
10000
17.6 mS/cm
3
30000
48.6 mS/cm
5
50000
81.0 mS/cm
10
100000
140 mS/cm
NOTE
For resistivity measurement the standard resistivity units of the calibration solution can be
calculated as follows:
R = 1000/G (kΩ•cm if G = μS/cm)
Example:
0.001% weight
R = 1000/21.4 = 46.7 kΩ•cm
Appendix 4 Sensor selection for the SC450G
Yokogawa supplies the following sensors, and their application is briefly described. All are
compatible with the SC450G, and the user must be aware of the sensor configuration for 2
or 4 electrodes, in order to set the converter correctly.
SC42-SP34 (&SX42-SX34)
cc = 0.01 cm
-1
2-electrode sensor
This sensor is the first choice for pure and ultra pure water measurements. From 0.055µS/
cm up to 100µS/cm this is a perfect choice. The measuring range extends to at least
1000µS/cm, but there are better choices in that range.
Almost exclusively used in flow fittings and sub-assemblies. FF40 and FS40. (The -SX
sensors are screwed or flanged direct into the process pipework or tanks.)
SC4A-S(T)-XX-002......
cc = 0.02 cm
-1
2-electrode sensor
This sensor is a good choice for pure and ultra pure water measurements. From 0.055µS/
cm up to 50µS/cm this is a good choice. The measuring range extends to 500µS/cm, but
there are better choices in that range. The “SC4A-” sensors make up a range that use
compression adapters or specialized fittings, including retractable.
SC42-SP24 (&SX42-SX24)
cc = 0.1cm
-1
2-electrode sensor
This sensor should be used for clean and pure water measurements. From 0.2µS/cm up
to 1 mS/cm the sensor is fine, with measurement up to 10mS/cm possible, but there are
better choices in that range. Mounting of these sensors is as for the ....-SP(X)34 series.
