ThermoFisher Scientific 146iQ, Instruction Manual

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Operation
Settings
3-74 146iQ Instruction Manual Thermo Scientific
●
Gas Flow: Shows the gas flow set value (as set in the gas setup
screen) and gas flow measured value. Note: For O
3
, this flow will be
the flow through the ozonator. For NO
2
, this flow will be the NO
flow though the gas MFCs. For permeation gas, this flow will be
the flow through the permeation oven.
●
Total Flow: Shows the total flow set value (as set in the gas,
ozonator, or permeation oven setup screen).
●
Photometer: Shows the photometer mode and reading, if installed.
The allowable modes are Off, Internal, External, and Control. In
Internal mode, the photometer is configured to take sample from
the manifold and report the ozone concentration. In External
mode, the photometer takes sample from the ‘External Sample’
rear-panel bulkhead fitting and reports the ozone concentration. In
Control mode, the photometer is configured the same as Internal
mode, and the ozonator drive signal is controlled to provide a pre-
set ozone concentration. This concentration is maintained by
constantly updating the drive signal to the ozonator lamp based on
the measured photometer concentration.
Note The Purge function is utilized to clear residual span gases from the
instrument’s pneumatics with the available zero air. Initiating Purge
through the Operation and Manual Operation screens or the Programmed
Events option will open the Purge and Zero Air valves such that zero air
goes through the Zero and Span Gas MFCs. The Zero air MFC is
automatically set to 2.5 SLPM and the Span Gas MFCs are set to 75% of
their full scale range such that there is highly responsive purging of the
MFCs and downstream lines as well as the mixing chamber, when initiated
through the Operation Screen. It is recommended to run the purge option
frequently, and to add the purge event at the end of every programmed
sequence. It should be noted that the purge event does not automatically
shut off, and should be ended by the user. The following illustrates how to
run the purge action through the Operation Screen.
▲
Home Screen>Settings>Operation>Gas (under Setting)