Hach 366 Serie Manual Básico Del Usuario página 24

6.6.3 Liquid or gaseous sample selection
Use the Configuration, Gas Phase to set the measurement phase (dissolved or gaseous) according
to application. Choose OK to confirm.
6.6.4 Specifying oxygen sensor interferences
Use the Configuration, Oxygen Sensor Interferences to eliminate the sensitivity of the oxygen sensor
to CO or H S in the sample measured. Select Insensitive to CO , Insensitive to H S, or None as
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appropriate. This screen is also used to correct oxygen measurements taken in high salinity or
chlorinity conditions. If required, select Chlorinity or Salinity and enter the chlorine or salt
concentration in the box provided, otherwise select None.
Operating the oxygen sensor in insensitive to H S mode requires a different sensor and electrolyte to
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be used in place of the standard oxygen sensor and electrolyte. Please contact your Hach Lange
representative for details.
6.6.5 Setting measurement units
Choose Configuration, Units to specify the measurement units for gas concentration and
temperature. The selected units are used for the instrument LCD display and appear in all ATEX
3660 displays, print outs, and data tables. When "composite" units are selected, such as ppm/ppb or
%/ppm, the instrument display will automatically switch between the units (auto ranging) when the
measurement drops below the minimum value of the higher units.
6.6.6 Membrane selection
Choose the Configuration, Membrane choice to review or select the membrane which is used in the
sensor. Using a different type of membrane in the sensor may be necessary to suit conditions.
Selecting another membrane from the software returns the instrument calibration to factory settings.
A warning message asks to continue. A calibration of the instrument is always required after
selecting a new membrane type.
6.6.7 Selecting calibration mode
Note: The calibration mode can be selected either from the instrument or from the software.
Use the Configuration, Calibration Mode to select whether the sensor is to be calibrated in air, in-line,
or in a calibration (span) gas. See Calibration on page 25 for details.
6.6.8 Calibration range check
When performing calibration, the instrument compares the sensor current to an ideal value, to
determine if the calibration makes sense. Enable or disable this calibration range checking for "In Air"
and "In a calibration Gas" calibration modes. It is recommended to leave this checking feature
enabled. In specific measurement situations, it may be necessary to disable range checking.
However, contact your Hach Lange representative before disabling this feature.
6.6.9 Calibration gas concentration
When calibrating the sensor in a calibration gas, use the Calibration (span) gas to enter the
concentration of the calibration gas used. Enter the percentage of gas concentration in the calibration
gas and then select OK.
6.6.10 Setting thermal cut-off
To protect the sensor, the thermal cut-off function allows for setting a sample high temperature limit.
If exceeded, the electrical signal to the sensor is cut off, and the system warns the user on the
display, and send an analog and digital signal. The temperature is factory set at 65º C, but can be
modified to suit conditions. After a thermal cut-off, the instrument restores the current supply to the
sensor when the sample temperature drops 2.5°C below the specified cut-off temperature.
6.6.11 Automatic or manual storage mode
The instrument will store up to 500 gas concentration measurement values, labeled as sample
numbers 0 through 499, with the date and time of the measurement. This information can be saved
manually or automatically. Choose the Configuration, Automatic Storage Mode command to select
an automatic storage mode.
If Timer mode is selected, measurements are stored at intervals defined by the Sampling Rate
command (see Sampling rate for the automatic storage mode on page 25). If Events mode is
selected, one measurement is stored when an event occurs, for each of the following events:
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