Measurement Units - Hach ORBISPHERE 3658 Manuel D'utilisation Simplifié

5.4 Configuring the instrument
The ORBISPHERE 3658 analyzer can be readily configured for your application using the following
commands in the Configuration menu. The instrument must be connected to your PC and powered
on, in order to change any configuration parameters.
5.4.1 Gas measurement phase
The instrument can measure CO
gas phase to use. Choosing the Hach 3658 program's Configuration, Gas Phase menu lets you
select the gas measurement phase.
The gas measurement phase can also be selected from the instrument keyboard as follows:
1. Switch the instrument power OFF.
2. Switch the instrument on by holding down the CAL button and then pressing the POWER button
while still pressing the CAL button.
3. The instrument display will first show PHA before switching to either dIS for dissolved or gAS for
gaseous measurements.
4. Use the Up/Down Arrow buttons to change the gas phase to your choice.
5. Press the MEAS button to save the selected gas measurement phase. The instrument then goes
to measurement mode.

5.4.2 Measurement units

Choose the Configuration, Units menu to select gas measurement units, temperature
measurement units, and the liquid medium in which you are measuring.
Using this dialog box, you can select:
• The Gas units in which gas concentrations are to be displayed
• For dissolved measurements: g/kg, % (by weight), V/V, cc/kg, mL/L, ppm/ppb, ppm or
mg/100mL
• For gaseous measurements: %/ppm (by volume), % (by volume), kPa/Pa, kPa, bar/mbar, bar,
bar20/mbar20 or bar20
• The Liquid medium for dissolved gas concentration measurements: Water, Beer, Cola or Wine
• The Temperature units for display: °C or °F
5.4.3 Membrane selection
Membrane 29561A is the only membrane valid for CO
ensure the analyzer is correctly configured, choose Configuration, Membrane to bring up the box
which reveals the membrane models available.
Membrane 29561A should be the only membrane available for selection. Select this membrane and
click on OK.
5.4.4 Automatic data acquisition - Setting sampling intervals
The instrument can perform as a standalone data acquisition device, automatically recording gas
measurements with the date and time, and storing up to 500 of these values. Choosing the Hach
3658 program's Configuration, Sampling Rate menu lets you select time intervals (acquisition rate)
for this storage capability.
Use the slide bar to view and select a sampling rate, from 15 seconds to 1 hour. The selected rate is
shown in the Acquisition rate window. Click OK to save this rate. Once your choice is made, the
instrument can be used independently of the Hach 3658 program for data acquisition. Refer to
Automatic data acquisition
Note: The Acquisition rate set via this menu is independent from the monitoring chart updating rate in
measurements in real-time
the chart updating rate is used only for displaying real-time results via the monitoring chart.
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in either a liquid or a gaseous sample, but you must select which
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on page 11.
on page 14. The sampling rate menu applies only to automatic data acquisition, while
gas measurement with this analyzer. To
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Monitoring