Operation
Range Menu
Thermo Fisher Scientific
Model 15
i
Instruction Manual
3-13
The Gas Units screen defines how the HCl concentration reading is
expressed. Gas units of parts per million (ppm) and milligrams per cubic
meter (mg/m
3
) are available. The mg/m
3
gas concentration mode is
calculated using a standard pressure of 760 mmHg and a standard
temperature of 20 °C.
When switching the selected units, 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 5000 ppm. Therefore, whenever you change
units, you should also check the range settings.
●
In the Main Menu, choose Range >
Gas Units
.
Note
If the units change from ppm to 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.
▲
GAS UNITS:
CURRENTLY: PPM
SET TO: MG/M3 ?
AND SET RANGES AND CAL TO
X
DEFAULT SETTINGS
XXXXXXXXXX
©ª
CHANGE VALUE
SAVE
RANGE AVG DIAGS ALARM
The Range screen defines the concentration range of the analog outputs.
For example, a HCl range of 0–50 ppm sets the analog output to
concentrations between 0 and 50 ppm by default.
The display shows the current HCl 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” and “Low” to indicate which range is displayed. The
following example shows the HCl range screen in single mode. For more
information about the dual and auto range modes, see “
Single Range
Mode
”, “
Dual Range Mode
”, and “
Auto Range Mode
” earlier in this
chapter.
Table 3–5
lists the standard ranges.
●
In the Main Menu, choose Range >
Range
.
Gas Units
Range
