Thermo Scientific 49i, Instruction Manual, Page: 50 / 314

Operation
Range Menu
3-14 Model 49
i
Instruction Manual Thermo Fisher Scientific
Gas Units
The Gas Units screen defines how the O
3
concentration reading is
expressed. Gas units of parts per billion (ppb), parts per million (ppm),
micrograms per cubic meter (
μ
g/m
3
), or milligrams per cubic meter
(mg/m
3
) are available. The
μ
g/m
3
and mg/m
3
gas concentration modes are
calculated using a standard pressure of 760 mmHg and a standard
temperature of 20 °C.
When switching the selected units from ppb or ppm to
μ
g/m
3
or mg/m
3
,
the analog ranges all default to the highest range in that mode. For example,
when switching from mg/m
3
to ppm, all the ranges default to 200 ppm.
Therefore, whenever you change units, you should also check the range
settings.
• In the Main Menu, choose Range > Gas Units .
• Use and to scroll through a list of choices.
• Press to save the new units.
Note If the units change from ppb/ppm to
μ
g/m
3
/mg/m
3
or vice-versa, the
instrument should be re-calibrated, particularly if the user’s standard
temperature is different from 20 °C. A display warning will appear that
ranges will be defaulted and calibration parameters reset.
O
3
Range
The O
3
Range screen defines the concentration range of the analog outputs.
For example, an O
3
range of 0–500 ppb restricts the analog output to
concentrations between 0 and 500 ppb.
The display shows the current O
3
range. The next line of the display is used
to change the range. The range screen is similar for the single, dual, and auto
range modes. The only difference between the screens are the words “High”
or “Low” displayed to indicate which range is displayed. For more
GAS UNITS:
CURRENTLY: PPB
SET TO: UG/M3 ?
AND SET RANGES AND CAL TO
X
DEFAULT SETTINGS XXXXXXXXXX
©ª
CHANGE VALUE
ƒ
SAVE
RANGE AVG DIAGS ALARM