Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 154)

<13. COMMISSIONING OF DO (Dissolved Oxygen)>
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IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
13.2 Measurement setup
In this section, set up various parameters relating to measurements.
Measurements are performed based on the measurement parameter setup.
If “Polarographic” is selected for “Sensor type” in the Sensor setup screen, the polarographic
application voltage can be set.
13.2.1 Sensor setup
Select a unit for sensors from mg/L, ppm, ppb, and %SAT. Select a value for sensor sensitivity
from 0.45 μA/ppm (50 µm), 0.90 μA/ppm (25 µm), and other. If you select “other,” enter an
appropriate value.
13.2.2 Temperature settings
Select the temperature element used for compensation from among Pt1000 and NTC22k. 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
13.2.3 Temperature compensation
Select “Manual” or “Automatic” for the temperature compensation type.
Select “Automatic” if the temperature sensor’s measured value is used or “Manual” if no
temperature sensor 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.
13.2.4 Salinity compensation
This function is used to measure sample water containing salt such as sea water.
The dissolved oxygen in a solution is affected by salinity. Therefore, to conduct accurate
measurements, it is necessary to compensate the influence of the salinity of the sample solution.
To make salinity compensation, select “Enabled” for “Compensation.”
Calculate the saturated concentration value from the salinity and temperature of the actual
sample water based on Table 1 of Appendix 4 (Solubility of oxygen in water as a function of
temperature and salinity) and enter the value.
13.2.5 Pressure comp. (Measure)
Dissolved oxygen concentration changes depending on changes in the process pressure or air
pressure. To compensate this, enter a value of pressure (air pressure).
See Tables 2 and 3 in the Appendix.
DO
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