Myron-l PS6FCE User Manual download pdf (Page 42)

varies with concentration and temperature in a non-linear fashion. Other

solutions have more variation still. The Po o l Pr o uses corrections that

change with concentration and temperature instead of single average

values. See Chart 1.

C. An Example of 2 different solution selections and the

resulting compensation

How much error results from treating natural water as if it were KCl at

15°C?

A tap water solution should be compensated as 442 with a tempco of

1.68 %/°C, where the KCl value used would be 1.90 %/°C.

Suppose a measurement at 15°C/59°F is 900 microsiemens of true

uncompensated conductivity.

Using a 442 correction of 10 (degrees below 25) x 1.68% indicates the

solution is reading 16.8% low. For correction, dividing by (.832) yields

1082 microsiemens as a compensated reading.

A KCl correction of 10 (degrees below 25) x 1.9% indicates the solution

is reading 19% low. Dividing by (.81) yields 1111 microsiemens for a

compensated reading. The difference is 29 out of 1082 = 2.7%.

Chart 1

0 5 10 15 20 25 30 35 40 45 50 55 60

1.500%

1.600%

1.700%

1.800%

1.900%

2.000%

2.100%

2.200%

2.300%

2.400%

2.500%

KCl % / °C

% / °C

Temperature

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 51 52

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Myron-l PS6FCE User Manual Page 42