LTH MOD53, Руководство по эксплуатации

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7 Parameters
44
SENSOR TYPE
The MOD53 can scale its input readings to operate with either a Galvanic
(Mackereth) or Polargraphic (Clark) sensor. This enables the instrument to be used
with a variety of different manufacturers’ sensors. Both types of sensor provide a
current output, but Polargraphic sensors require a polarising voltage to be applied
across the Anode and Cathode. Other parameters will need to be set such as the
bias voltage, membrane correction and temperature sensor type. These settings
will need to be obtained from the manufacturer of the sensor
TEMPERATURE INPUT
Temperature has a significant effect on the output from the sensor, and it is
therefore necessary to compensate for the variations in the liquid and the sensor.
The MOD53 provides the facility to measure and automatically compensate for
these temperature variations, or alternatively, if no temperature sensing is
available, the user can select manually the temperature at which the unit
compensates. It is recommended that unless a stable measurement temperature
is achievable, the automatic compensation be used.
The operator can apply automatic or manual temperature compensation to the
dissolved oxygen measurement by selecting the mode of operation in the “
T.
Comp.” menu item within the “ Parameters” menu. For automatic compensation,
the correct temperature sensor must be selected in the Configuration menu. When
the manual mode of operation is selected the user can enter the fixed process
temperature under the
Fixed Temp. Menu. { Note. When the automatic mode is
selected the Fixed Temp. menu will not be present } .
NOTE : If a Temperature sensor fault is detected, the unit defaults to the “ Fixed
Temp” setting for compensation purposes, and displays an error condition.
The operator can choose to display all temperatures in
°
C or
°
F by modifying the
“ T. Units” parameter. All temperature related displays will use the units selected
in this menu. N.B. The system will normally convert all temperature related
variables when the units are changed, however it may be wise for the operator to
ensure that changing the units has not altered the set points or current outputs.
SALINITY
The salinity of the solution has a significant effect when converting % Saturation to
concentration. The user can compensate for this by setting the
“Input Salinity ”
parameter to the correct level. (Entered in ppt, parts per thousand).