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MODEL SOLU COMP II SECTION 8.0
TROUBLESHOOTING
8.7 SIMULATING INPUTS — CONDUCTIVITY
To check the performance of the analyzer, use standard resistors to simulate conductivity.
A. Set the temperature correction to raw (Section 5.5).
B. Connect the standard resistors to TB-5 as shown in
Figure 8-4.
C. Determine how closely the displayed resistivity or
conductivity agrees with the known resistance.
To convert resistance to conductivity, use the equation:
Conductivity (µS/cm) = x 10
6
or
Conductivity (mS/cm) = x 10
3
Thus, if the cell constant is 0.103/cm and the standard resistance is 500 Ω, the displayed conductivity should
be (0.103/cm)(10
6
)/(500Ω) or 206 µS/cm.
To convert resistance to resistivity, use the equation:
Resistivity (MΩ-cm) =
Thus, if the cell constant is 0.01020/cm and the standard resistance is 100 kΩ (0.100 MΩ), the displayed resis-
tivity should be (0.100 MΩ)/(0.01020/cm) or 9.80 MΩ-cm.
Consult the table for the accuracy specification:
*whichever is greater
D. If the analyzer does not meet the accuracy specifications, it can be recalibrated. See Section 6.10.
Cell constant (/cm)
Resistance (Ω)
Cell constant (/cm)
Resistance (Ω)
Resistance (MΩ)
Cell constant (/cm)
Range Cell constant (/cm) Accuracy*
0.055 - 10 µS/cm 0.01 ±0.9% of reading
or ±0.002 µS/cm
0.055 - 50 µS/cm 0.01 ±2% of reading
0.055 - 500 µS/cm 0.1 ±2% of reading
or ±0.1 µS/cm
0.055 - 5000 µS/cm 1.0 ±2% of reading
or ±1 µS/cm
0 - 5 mS/cm 1.0 ±2% of reading
or ±0.001 mS/cm
0 - 20 mS/cm 10 ±2% of reading
or ±0.01 mS/cm
10 - 20 MΩ-cm 0.01 0.9% of reading
FIGURE 8-4. Simulating Conductivity
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