Hach ORBISPHERE 3658 Manuel D'utilisation Simplifié page 11

displayed on the LCD. Once the tests are completed, a clearing message [---] is displayed for a
further sixty seconds before the instrument switches automatically to measurement mode.
Note: The start-up tests will be repeated until successful, or for a maximum of 15 minutes. If the tests are still
unsuccessful after 15 minutes, a [Err] message will be displayed and the instrument locked. Turn the instrument off
and retry the start-up procedures, but if the problem persists, please contact your local Hach Lange service
representative for assistance.
Measurement updates are displayed every 20 seconds, and it is normal for the right-most digits to
vary in reaction to slight variations in gas content. For accurate measurements, the sensor's
membrane must be at the same temperature as the sample to be analyzed. If this not the case, allow
some sample to pass through the flow chamber for about 3 minutes before taking any
measurements.
The LCD includes a right-side marker to distinguish between gas concentration measurements and
temperature. This marker also indicates the measurement display units (k/kg, V/V, etc. depending on
the instrument configuration).
To switch between gas measurement and temperature measurement, press the Up/Down Arrow
buttons. To illuminate the LCD for approximately three minutes, press the Backlight button.
4.2.1 Select gas measurement phase
Ensure the gas measurement phase is correct for this measurement. For details on viewing the
current setting, refer to
setting, refer to Gas measurement phase
4.2.2 Measurement mode
You can set the measurement mode to normal or maximum. For details on how to do this refer to
Measurement mode on page 17.
Maximum mode facilitates making measurements in bottles and cans. To search for a maximum
measurement value, press the MEAS button.
• The LCD first shows the message [run] for a few seconds, before displaying measurement values.
• After a 60 second measurement cycle, the instrument searches for two consecutive gas
measurements with less than 2% difference. When this condition occurs, the displayed value
freezes on the LCD (indicated by a blinking display), allowing you to note down or store the data.
The display remains frozen until you press the MEAS button to make a new measurement, or you
select normal measurement mode (as described in
4.3 Storing measurements in the instrument
The analyzer will store up to 500 gas concentration and temperature measurement values, labeled
by numbers 0 through 499, along with the current date and time of each measurement. You have the
choice of acquiring this information manually or automatically, as described below.
Note: Do not put the instrument into standby while it is in the process of storing data, otherwise the data values will
be lost.
Before storing measurements, you should verify the date and time settings of the instrument's
internal clock, as described in
4.3.1 Automatic data acquisition
Note: When the instrument is used to automatically store measurement data, all buttons except the POWER key
are disabled. If enough time elapses to store all 500 values, the instrument will return to normal measurement mode
and the buttons re-enabled.
Before starting automatic measurement storage, first select the sampling rate desired using the Hach
3658 program. Refer to
1. Put the instrument into standby (by pressing the POWER key).
2. Then hold down the STO button while switching the instrument back ON. The LCD displays the
message Sto for about one second.
3. Normal gas concentration measurements are displayed for about two minutes.
Reviewing instrument configuration
on page 16.
Clock settings
Automatic data acquisition - Setting sampling intervals
on page 15. For details on changing this
Measurement mode
on page 24.
on page 17).
on page 16.
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