42/24-10 EN Rev. 9
Chapter 9: Inspection and Maintenance
9-29
Air Pressure Value Correction
An incorrect air pressure value will produce erroneous measurement values.
When should the air
pressure value be
set?
The air pressure value must be checked and readjusted as required in the
following cases:
•
If the gas analyzer’s operating site altitude has changed since the last calibration
•
If the air pressure effect on the measured value is too high (see also Appendix 2,
“Analyzer Module Operating Specifications”).
Limas11 and Uras26
with Integral Pressure
Sensor and
Calibration Cells
A pressure sensor is factory-installed in the Limas11 and Uras26 analyzer
modules. The pressure sensor is calibrated to 1013 hPa. This is the reference
pressure for the test gas concentration when measuring the calibration cells.
If the air pressure value needs to be changed, the following items are also
required
•
Calibrate the sample components with test gases and then
•
Measure the calibration cells
Air Pressure Value
Correction
The current atmospheric pressure can be entered as a correction value for each
analyzer module or for all analyzer modules as a group.
Menu Path
For one analyzer module:
MENU
→
Maintenance/Test
→
Analyzer spec. adjustm.
→
Atm. press. anlz
→
...
For all analyzer modules as a group:
MENU
→
Maintenance/Test
→
System
→
Atm. pressure
If the pressure sensor is connected to the sample gas output line, the sample gas
flow must be interrupted while calibrating the pressure sensor so that the sample
gas pressure does not distort the measured pressure.
