Myron L TechPro II, Operation Manual

Page: 31 / 44

27
Users wanting to measure natural water based solutions to 1% would
have to alter the internal compensation to the more suitable preloaded
“442” values, or stay close to 25°C. Users who have standardized to KCl-
based compensation may want to stick with it, regardless of increasing
error as you get further from 25°C. The TechPro II will provide the
repeatability and convertibility of data necessary for relative values for
process control.
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 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 TechPro II gives the user the capability to collect data in “KCl
conductivity units” to compare to older published data, as in terms of
NaCl or 442, or as appropriate.
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