Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 218)

App.2-2
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
A. Calculation of temperature coefficient factor (With known conductivity at reference
temperature).
K
t
- K
ref
α =
T - T
ref
100
K
ref
X
α = Temperature compensation factor in %/°C
T = Measured temperature in °C
K
t
= Conductivity at T
T
ref
= Reference temperature
K
ref
= Conductivity at T
ref
B. Calculation of temperature coefficient factor (with two known conductivity values at
different temperatures)
Measure the conductivity of the liquid at two temperatures, one below the reference and
above the reference temperature with the temperature coefficient set to 0,00%/°C and use
the following equation to calculate a temperature coefficient (α).
K
T
K
ref
=
1+α ( T - T
ref
)
K
2
- K
1
α =
K
1
( T
2
- T
ref
) - K
2
( T
1
- T
ref
)
K
1
K
2
K
ref
= =
1+α ( T
1
- T
ref
) 1+α ( T
2
- T
ref
)
K
1
(1 + α ( T
2
- T
ref
)) = K
2
(1 + α ( T
1
- T
ref
))
K
1
· α ( T
2
- T
ref
) - K
2
· α ( T
1
- T
ref
) = K
2
- K
1
Where T
1
, T
2
: liquid temperature (°C)
K
1
: conductivity at T
1
(°C)
K
2
: conductivity at T
2
(°C)
( )
(
(
Figure 1 Conductivity