Technical information

APPENDIX C
3/31/2008 Rev. 4.3 C - 3
Figure C-1: Configuration for the CI-301AD Adjustable Humidity and CO
2
Control Module.
OPERATION
NOTE: The CI-301AD does not supply gas under pressure to the output. This is because constant
flow must be established inside the unit to maintain stability; unused gas is exhausted inside the case.
Gas must be drawn from the output by the analyzer or an external pump. When connected to the CI-
340 CO
2
gas analyzer, the pumps inside the Analyzer will draw the gas from the CI-301AD into the
analyzer system. An external pump may be required if using a different analyzer.
Do not attempt to draw more than 0.5 LPM (liter per minute) from the CI-301AD output. Doing so
may result in ambient air being drawn into the system, causing inaccurate results.
The CI-301AD must be fully upright to operate (with the control panel facing upwards). This is
necessary for two reasons. First, the soda lime and silica gel cartridges operate most efficiently in a
fully upright position. Second, if the unit were to tip too far in operation, liquid might enter the
system and be pumped to the analyzer, causing potential damage. If the unit is to be carried while in
operation, care should be taken to avoid tipping or shaking. This may cause power fluctuations, which
could temporarily affect stability.
To begin operation, turn the power on. This should be done 5 to 10 minutes before the system is to be
used, allowing time for the flow to stabilize. It may take about 5 to 10 minutes to purge the system
thoroughly. Set the CO
2
fully on during this time. The fastest way to purge the CO
2
chamber the first
time it is used after standing for a long period of time is to turn the CO
2
fully on, then turn the CO
2
fully off several times. This will cause ambient air that is trapped in the chamber to be replaced with
pure CO
2.
Turn the H
2
O knob to adjust the relative humidity. This must be done before adjusting the CO
2
level,
since changes will affect the CO
2
concentration. The desiccant used to control humidity absorbs CO
2
gas.
Turn the CO
2
knob to adjust the CO
2
level. There is a slight delay before stabilization occurs It will
generally take a minute or so to fully stabilize (assuming the CO
2
chamber has been previously filled
with CO
2,
or 2 to 10 minutes if it has not been filled with CO
2
).
To enable the CI-340 instrument to control the CO
2
/ H
2
O levels remotely, the accessory cable must
be connected to the CI-340 and the yellow color-coded plug must be inserted into the remote control
jack of the CI-301AD. Turn the CO
2
knob fully counterclockwise and the H
2
O knob fully clockwise.
REPLACING THE CONSUMABLES
The CI-301AD requires periodic replacement of the CO
2
, soda lime, silica gel, water, and filters. All
materials should be available locally through chemical or laboratory supply dealers, or they may be
ordered from CID, Inc.