Thermo Scientific MIRAN 205B Series, Instruction Manual, Page: 42 / 214

Chapter 5 Analysis
5-2
To re-zero the analyzer, press 1 (New zero) from the Zero Menu. The display responds
with "Please wait..." and/or "Please wait while system warms up...". When all areas are
indicated "ok", press
ENTER
to continue. If the Analyzer mode is not zero, or scan and
pressure compensation is configured On, the display shows the current pressure
compensation and gives the user the opportunity to accept or change it. If a new pressure
is entered, the display responds "-ACCEPTED-" or presents an "!INVALID VALUE!"
message. Next, the analyzer checks its pathlength. The analyzer is set to one of two
pathlengths; short (0.5 m) or long (12.5 m). If the pathlength is not correct for the
application, the display prompts the user to change the pathlength (see Chapter 4,
“Changing the Pathlength”).
┌────────────────────────────────────────┐
│╒══ CURRENT APPLICATION ══╕ │
││ │ │
││ │ Install │
││ │ chemical │
││ METHANE: ---- ppm │ filter │
││ │ │
││ │ │
│└───────────────────────┘ Enter=Continue │
└────────────────────────────────────────┘
Install Chemical Filter Display
┌────────────────────────────────────────┐
│╒══ CURRENT APPLICATION ══╕ Wait for cell │
││ │ to fill with │
││ │ sample... │
││ │ │
││ METHANE: ---- ppm │ 15 seconds │
││ │ │
││ │ │
│└───────────────────────┘ Enter=SkipPurge │
└────────────────────────────────────────┘
Zeroing Process Display
Caution: The zero process requires five volumes of air (about 11 liters) to completely
purge the cell. Shortcutting this step can result in an incomplete purge and a faulty
baseline value. If ENTER is pressed to skip the purge, a message is displayed citing the
need to completely flush the cell. If the purge continues to be skipped, an error flag ("Z")
appears next to the displayed data because the automatic routine has been overridden.
Any measurement data is flagged with a "Z" for invalid data. Yet, it is possible that the
data is perfectly acceptable.
The display next prompts for the
installation of the chemical (zero)
filter on the connector as shown in
Figure 3-4. When this is done ,
press ENTER.
Wait for the cell to fill with zero
air and for the zeroing process to
occur. Press ENTER to shortcut
the purge.