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The instrument will be stabilizing for several seconds. Then data output will be displayed. Use the
arrow keys on the keypad to scroll up and down to view all the data.
Closed and Open Systems
The CI-340 promotes a portable solution to the concept behind open and closed systems. A closed
system environment can measure the CO
2
concentration in the chamber over a given period of time. An
open system environment can measure CO
2
concentration in the chamber by a steady air stream flow.
At any rate (0.2 to 1.0 lpm), this instrument provides another practical method to determine
photosynthesis, transpiration, and stomatal conductance.
The physical distinction between the two systems is with the accessory tubing attachment (Figure 9).
The open system utilizes a steady stream of fresh air; the closed system recirculates the air within the
analyzer environment. Figure 10 illustrates further the CI-340’s closed and open system flow chart.
Figure 9. The CI-340 accessory tubing attachment.
Note: The tubing accessory should not be kinked or restricted during operation. A replacement
tube can be used; it should be of vinyl or polyurethane material and approximately 5” long. Tygon
B-44-3 is normally used because it does not absorb much moisture.
Figure 10 (top). Tubing schematic for a closed system. (bottom). Tubing schematic for an open system.
A supplied filter should be connected between the inlet and the tubing.
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