Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 58)

<4. COMMISSIONING OF pH/ORP>
4-4
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
4.2.2 Temperature settings
Select the temperature element used for compensation from among Pt1000, Pt100, 3kBalco,
8k55, PTC10k, 6k8, and 500Ω. Select the same type as the temperature element that is actually
connected.
Celsius (°C) or Fahrenheit (°F) temperature units are available. If the unit is changed, the
following values are also recalculated automatically to the new unit:
• Manual temp.
• Reference temp.
• Temp. coefficient
• Temp. ranges in the matrix
4.2.3 Temperature compensation
ORP measurement involves no temperature input. No setting is required on the temperature
compensation. Process temperature compensation is effective if “T.C. ORP mV/°C” in “Temp.
Coef.” is set.
n Temperature compensation
This compensation of pH value is performed on the Nernst equation.
Two methods can be used: Automatic and Manual. Select Automatic when a temperature
element is used, or select Manual when a manually set temperature is used.
NOTE
When Manual is selected on the Temperature compensation, a process temperature should be
set in the “Manual temp.” A temperature shown on the Main display or the Home display is this
manually set temperature.
n Reference temperature
Set a reference temperature to which the measured pH value must be compensated. Normally
25°C is used, so this temperature is chosen as the default value.
n Process temperature compensation
Select a temperature compensation method. “None” does not perform the temperature
compensation.
If “pH” is selected in “Sensor type,” choose process temperature compensation from among
None, TC, Matrix, and NEN6411. If “ORP” is selected in “Sensor type,” choose it from among
None and TC.
l
TC
This method uses the linear compensation function.
It is possible to adjust the temperature coefficient (TC) factor directly. If the temperature
coefficient factor of the sample liquid is known from laboratory experiments or has been
previously determined, it can be entered here.
This TC is a pH variation to 1 °C (∆pH/∆T). Adjust the value between -0.1 to 0.1 pH/ºC.
In combination with the reference temperature setting, a linear compensation function is
obtained, which is suitable for all kinds of chemical solutions.