Myron L 6Pfc and 4P - Manual (Page 43)

39
7%
Chart 2
55
(1)%
(2)%
0%
1%
2%
3%
4%
5%
6%
0 5 10 15 20 25 30 35 40 45 50
Temperature
NaCl error with KCl tempco
442 error with KCl tempco
E. Other Solutions
A salt solution like sea water or liquid fertilizer acts like NaCl. An internal
correction for NaCl can be selected for greatest accuracy with such
solutions. Many solutions are not at all similar to KCl, NaCl or 442. a
sugar solution, or a silicate, or a calcium salt at a high or low temperature
may require a User value peculiar to the application to provide readings
close to the true compensated conductivity.
Clearly, the solution characteristics should be chosen to truly represent
the actual water under test for rated accuracy of ±1%. Many industrial
applications have historically used relative measurements seeking a
number to indicate a certain setpoint or minimum concentration or trend.
The Ultrameter II gives the user the capability to collect data in “KCl
conductivity units” to compare to older published data, in terms of NaCl
or 442, or as appropriate. The Ultrameter II can be used to reconcile
data taken with other compensation assumptions, especially with its
ability to allow custom characteristics through the User mode.
XXI. CONDUCTIVITy CONVERSION to TOTAL
DISSOLVED SOLIDS (TDS)
Electrical conductivity indicates solution concentration and ionization
of the dissolved material. Since temperature greatly affects ionization,
conductivity measurements are temperature dependent and are
normally corrected to read what they would be at 25°C (ref. Temperature
Compensation, pg. 37).