Cell K Factor
mS/cm
uS/cm
uS/m
Substitute
resistance
K=10.0
100
100,000
10,000,000
100Ω
K=10.0
10
10,000
1,000,000
1,000Ω
K=10.0
1
1,000
100,000
10,000Ω
K=1.0
10
10,000
1,000,000
100Ω
K=1.0
1
1,000
100,000
1,000Ω
K=1.0
0.1
100
10,000
10,000Ω
K=1.0
0.01
10
1,000
100,000Ω
K=0.1
1
1,000
100,000
10Ω
K=0.1
0.1
100
10,000
1,000Ω
K=0.1
0.01
10
1,000
10,000Ω
K=0.1
0.001
1
100
100,000Ω
6.11
Standard ppm conversion factors
The
ppm FACt
(ppm factor) function value is used with the input from the cell to calculate the
ppm value of the solution concerned. The displayed ppm figure is calculated from:
ppm
=
conductivity
(
uS/cm
)
×
P P mF ACt
The factor will vary with the composition and concentration of the solution being measured. Sug-
gested ppm factors for four standard solutions are given below. The suggested factors are based on
conductivities of approx. 14,000 uS/cm at 25
o
C. For example the default setting for the instrument
is 0.560 which is a figure used for NaCl (sodium chloride solution or salt water).
Standard solution
Use
Suggested
PPM FACt
value
NaCl
Salt water and dairy products
0.560
442
General fresh water e.g.
(40% sodium sulphate,
rivers, lakes and reverse
0.860
40% sodium bicarbonate,
osmosis water
20% sodium chloride)
Can be used in applications
a NaCl standard is used but
KCL
is normally used as a
0.580
conductivity standard
rather than ppm standard
CaCO3
Boiler and cooling tower water
0.480
Returning to the normal measure mode
When the calibration procedure has been completed, it is advisable to return the instrument to
the normal mode (where calibration functions cannot be tampered with). To return to the normal
mode turn off power to the instrument, wait a few seconds and then restore power.
44 of
PM4COMAN-2.2-1
