Technical information

TECHNICAL INFORMATION
3/31/2008 Rev. 4.3 2-1
TECHNICAL INFORMATION
The CI-340 is a highly technologically advanced photosynthesis system. It contains a pump along
with a mass airflow sensor. A built-in microprocessor regulates the airflow rate, which is set by the
user. A technical diagram (Figure 2-1) illustrates a flow chart for this instrument. An illustration of
the CI-340 is on the following page (Figure 2-2).
The measurement process begins with an air/gas sample passing a solid-state CO
2
analyzer. The
output of the analyzer is amplified, sampled by an analog-to-digital (A-D) converter, and sent to the
microprocessor. The processor averages these readings and corrects them for any non-linearity
present in the analyzer.
A relative value of CO
2
concentration is continually updated by the microprocessor. Each reading
reflects sampling taken every second during a specified time period. This can be determined by
setting the time interval. The rate at which samples are saved in memory is determined by the
“sampling rate” or the time interval input at the beginning of each measurement session.
CAUTION: When attaching a pressurized gas source to the external inlet, use a three-way fitting
(which is provided with each instrument) to allow excess gas to escape. Excess pressure may blow
out internal fittings and tubing, or damage the pump. Do not use a three-way fitting for non-
pressurized gas sources.
Figure 2-1. Flow chart diagram.