YOKOGAWA SC450G - Appendix 4 Sensor Selection for the SC450 G

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brieydescribed.Allare
compatiblewiththeSC450G,andtheusermustbeawareofthesensorconguration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rst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anged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ttings,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.