Yokogawa EXAxt PH450 4-Wire Analyzer for pH and ORP - Manual (Page 32)

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IM 12B07C05-01E
5-1. Sensor setup
Sensor type: The sensor connection to the ter-
minals is determining the setting
of this parameter. Three selec-
tions can be made here.
pH: Only pH needs to be measured.
The glass electrode is connected to
terminal 15 and the reference is con-
nected to terminal 13.
ORP: Only Redox needs to be measured.
The metal is connected to terminal
15 and the reference (or glass) is
connected to terminal 13.
pH+ORP: When pH and ORP are measured
simultaneously the glass electrode
is connected to terminal 15 and the
reference is connected to terminal
13. The metal electrode is connected
to terminal 14. In this setup it is also
possible to measure rH.
Note! For best results a Liquid Earth is
connected to terminal 14. If there is no
LE terminal 13 and 14 are shortcutted
and no sensor diagnostics are possible.
This setting determines the menu
structure thoughout the instrument
5-2. Measurement setup
Measurement which process values.
This setting determines will be available for
monitoring and control.
5-3. Temperature setting
Temperature Element
Selection of the temperature sensor used for
compensation. The default selection is the
Pt1000 Ohm sensor, which gives excellent
precision with the two wire connections used.
The other options give the flexibility to use a
very wide range of other sensors.
Unit
Celcius or Fahrenheit temperature scales can
be selected to suit the user’s preference.
Manual temp., reference temp., temp. coef-
ficient and temp. ranges in the matrix are re-
calculated automatically to the new unit.
5-4. Temperature compensation
Two types of methods can be used here.
Automatic when a temperature element is
used. Select one of the Temp. elements used.
The other is a manual set temperature, which
represent the temperature of the process. The
latter is used when temperature measurement
is difficult and temperatures do not vary much.
Reference Temperature
Choose a temperature to which the measured
pH value must be compensated. Normally 25°C
is used, therefore this temperature is chosen as
default value.
Process Temperature Compensation
TC
It is possible to adjust the compensation factor
directly. If the compensation factor of the sam-
ple liquid is known from laboratory experiments
or has been previously determined, it can be
introduced here. Adjust the value between -0.1
to 0.1 pH/ºC. In combination with the reference
temperature setting a linear compensation
function is obtained, suitable for all kinds of
chemical solutions.
Matrix
The EXAxt is equipped with a matrix type algo-
rithm for accurate temperature compensation in
various applications. Select the range as close
as possible to the actual temperature/pH range.
The EXAxt will compensate by interpolation
and extrapolation. Consequently, there is no
need for a 100% coverage. See Appendix 3 for
matrix interpolation.
NEN6411
This is a NEN standard and applicable for
many applications. It’s used for pH compen-
sation in water applications using a glass
electrode. The calculation is base on Ultra Pure
Water (UPW) and is also valid for all strong
acids and strong bases. The main application is
in demiwater and boiler feed water/condensate.
5. MENU STRUCTURE COMMISSIONING