Thermo 49i, Инструкция по эксплуатации, Страница: 38 / 276

Operation
Range Menu
3-8 Model 49
i
Primary Standard 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 5 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.
Table 3-2 lists the standard ranges.
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