IM 12D08N04-01E
5-20
5. Parameter Setting
5-3-3. Temperature compensation functions
Code 20
*T.R.
°
C
Choose a temperature to which the measured conductivity (or resistivity) value
must be compensated to. Normally 25
°
C is used, therefore this temperature is
chosen as default value. Limitations for this setting are: 0 to 100
°
C.
If T.UNIT in code 11 is set to
°
F, default value is 77
°
F and the limitations are
32 - 212
°
F.
Code 21
*T.C.1/T.C.2
In addition to the procedure described in section 5-2-5 it is possible to ad-
just the compensation factor directly. If the compensation factor of the sample
liquid is known from laboratory experiments or has been previously determined,
it can be introduced here.
Adjust the value between 0 to +3.5 % per
°
C. In combination with reference
temperature setting in code 20 a linear compensation function is obtained,
suitable for all kinds of chemical solutions.
Code 22
*MATRX
The EXA is equipped with a matrix type algorithm for accurate temperature
compensation in various applications. Select the range as close as possible to
the actual temperature/concentration range. The EXA will compensate by
interpolation and extrapolation. Consequently, there is no need for a 100%
coverage.
If 9 is selected the temperature compensation range for the adjustable matrix
must be configured in code 23. Next the specific conductivity values at the
different temperatures must be entered in codes 24 to 28.
Code 23
*T1, T2, T3, T4 & T5
°
C
Set the matrix compensation range. It is not necessary to enter
equal temperature steps, but the values should increase from T1 to T5, other-
wise the entrance will be refused. Example: 0, 10, 30, 60 and 100
°
C are valid
values for the T1....T5. The minimum span for the range (T1 - T5) is 25
°
C.
Code 24-28 *L1xT1 -L5xT5
In these access codes the specific conductivity values can be
entered for 5 different concentrations of the process liquid; each one in one
specific access code (24 to 28). The table below shows a matrix entering ex-
ample for 1 - 15% NaOH solution for a temperature range from 0 - 100
°
C.
Notes:
1. In chapter 10 a table is included to record your programmed values. It will make
programming easy for duplicate systems or in case of data loss.
2. Each matrix column has to increase in conductivity value.
3. Error code E4 occurs when two standard solutions have identical conductivity values
at the same temperature within the temperature range.
Table 5-2. Example of user adjustable matrix
Matrix
Code 23
Code 24
Code 25
Code 26
Code 27
Code 28
Temperature
Solution 1(1%)
Solution 2(3%)
Solution 3(6%)
Solution 4(10%)
Solution 5(15%)
T1...T5
L1
L2
L3
L4
L5
Example
0 ˚C
31 mS/cm
86 mS/cm
146 mS/cm
195 mS/cm
215 mS/cm
Example
25 ˚C
53 mS/cm
145 mS/cm
256 mS/cm
359 mS/cm
412 mS/cm
Example
50 ˚C
76 mS/cm
207 mS/cm
368 mS/cm
528 mS/cm
647 mS/cm
Example
75 ˚C
98 mS/cm
264 mS/cm
473 mS/cm
692 mS/cm
897 mS/cm
Example
100 ˚C
119 mS/cm
318 mS/cm
575 mS/cm
847 mS/cm
1134 mS/cm