TARGAS-1 Operation Manual V. 1.02  80  support@ppsystems.com 
 
Appendix 2.  Soil CO
2
 Efflux and Net Canopy CO
2
 Flux on page 150. 
 
 
 
 
 
 
 
 
 
 
CPY (Canopy Assimilation Chamber) Process 
This process is used in conjunction with our CPY-5 Canopy Assimilation Chamber for measurement of 
closed-system net canopy CO
2
 flux. In the CPY process, the assimilation rate (μmol m
-2
 s
-1
) is calculated 
by measuring the rate of change (decrease) in the chamber CO
2
 
concentration. The TARGAS-1 
calculates both a linear fit and a quadratic fit to the measured data. The data is checked in the quadratic 
fit to determine if the data is linear. 
While the TARGAS-1 is in the CPY measurement mode, additional data is added to the output data 
string: change in CO
2
 (dC), process time (dT), Linear respiration rate (L), and Quadratic respiration rate 
(Q).  
Connecting the CPY-5 Canopy Assimilation Chamber to the TARGAS-1 
 
The CPY-5 Canopy Assimilation Chamber has one electrical 
connection and two pneumatic connections.  The electrical 
connection is made to the socket labeled PLC on the 
TARGAS-1 and the pneumatic connections are to the GAS 
IN and GAS OUT connectors as shown here.  The tubing on 
the CPY-5 is labeled accordingly for gas connections.  An air 
filter is also included on the GAS IN line on the CPY-5.  For 
best results we also recommend using the H
2
O equilibrator 
(Part No. 10049-2) on the GAS IN line as shown to assist 
with reducing the build-up of humidity in the gas stream.  
 
CPY – Start Process (Step 1) 
The first screen asks the user to confirm that they would like to start the CPY process.