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PR-23 instrucon manual
3. The chemical curve: The Indicating transmitter DTR receives n
D
and TEMP and cal-
culates the concentration value according to chemical curves derived from avail-
able chemical literature and K-Patents expertise. The result is a temperature com-
pensated calculated concentration value CALC.
4. Field calibration: Adjustment of the calculated concentration value CALC may be
required to compensate for some process conditions or to it the measurement to
the laboratory results. The Field calibration procedure, Section 6.4.3, determines
the appropriate adjustment to CALC. The adjusted concentration is called CONC.
If there is no adjustment, CALC and CONC are equal. Thus the chemical curve is
kept intact as a irm base for the calculation, the adjustment is merely additional
terms.
5. Damping: See Section 6.1.
6. Output signal: The range of the 4 to 20 mA signal is deined by its two endpoints
on the CONC scale, see Section 6.3.3.
6.4.1 The chemical curve
The chemical curve is the theoretical concentration curve based on n
D
and TEMP. It is
deined by a set of 16 parameters (Table 6.1, one set for each sensor).
C
00
C
01
C
02
C
03
C
10
C
11
C
12
C
13
C
20
C
21
C
22
C
23
C
30
C
31
C
32
C
33
Table 6.1 The chemical curve parameters
A chemical curve is speciic to the given process medium, e.g. sucrose or sodium hy-
droxide. The set of parameters is given by K-Patents and should not be altered, except
in case of changing to another process medium. The parameters can be changed by
selecting irst 5 CALIBRATION from the Main menu, then, in the Calibration menu, 1
CHEMICAL & FIELD PARAMETERS, and inally 1 CHEMICAL CURVE PARAMETERS.
6.4.2 Selecng display units and display decimals
The display units and display decimals are set separately for each sensor, so irst go to
the Calibration menu of the correct sensor. Then select 2 OUTPUTS in the Calibration
menu and in the Outputs menu choose either 1 DISPLAY UNITS or 2 DISPLAY DECIMALS.
For the display units, select either 1 CONCENTRATION or 2 TEMPERATURE and then the
unit. For display decimals, enter the number of decimals you want to see on display
by entering a number in the range 0–5 (0 meaning no decimals are shown).
Note: Change of concentration unit will not change the numerical value of the con-
centration. Change of temperature unit will recalculate the numerical temperature
value according to selected scale (°C or °F).