![Hach ORBISPHERE 3654 Скачать руководство пользователя страница 22](http://html.mh-extra.com/html/hach/orbisphere-3654/orbisphere-3654_basic-user-manual_577084022.webp)
Figure 5 Calibration setup diagram
1
Needle valve
4
Pressure valve
2
Accurate pressure gauge
5
Beaker of water
3
Flow chamber
6
Pure gas supply
7.2.2 Calibration at atmospheric pressure
The sensor can be calibrated in pure H
2
or N
2
gas at atmospheric pressure.
To ensure that the flow chamber and sensor components are dry, remove and blow dry the flow
chamber. Dry the sensor head surface with a clean soft tissue.
The analyzer uses an internal barometric pressure sensor during this calibration. First check that the
pressure sensor is correct and does not need recalibrating. If it does need to be recalibrated then
follow the instructions in
Barometric pressure sensor calibration
on page 20 before attempting this
calibration.
1.
Set the gas measurement phase to
Gaseous
the calibration medium to
In measured pure gas at atmospheric pressure
. Refer to
on page 20.
2.
Connect a source of pure H
2
or N
2
gas to the inlet of the flow chamber. Refer to
on page 21. Adjust the gas flow to one bubble per second when the exit tube is immersed in
water.
3.
Press the
CAL
button. Remember, this button may have been locked out to prevent an accidental
Locking out the instrument’s CAL button
4.
A brief clearing message
[---]
appears.
5.
Press
CAL
again within a 3 second period.
If the instrument makes two consecutive measurements with less than 1% difference, it calibrates
against this stabilized value. The LCD then displays the message
[CAL]
to indicate calibration
has been successfully completed
If the calibration does not complete, the LCD displays the message
[Err]
. The reason for this
calibration error is either that the measured gas partial pressure is under 5 mbar, or that a wrong
instrument key was pressed during the calibration steps.
7.2.3 Calibration at elevated pressure
The sensor can be calibrated in pure H
2
of N
2
gas at an elevated pressure. This method requires an
accurate pressure gauge connected to the exit of the flow chamber.
22
English